Chief Horticulture Officer
I’ve seen your recent recommendations for floodplain-tolerant trees and shrubs. With yet another May record rainfall I think I’d better get more serious about the “boggy” area of my garden that has standing water for a few hours after heavy rains. What perennials would you recommend for areas that frequently flood and will be winter hardy if their roots are wet all winter?
Sedges (Carex), Goatsbeard (Aruncus), White Turtlehead (Chelone), Hardy Hibiscus (Hibiscus), Sedges, Cardinal Flower (Lobelia), Rodger’s Flower (Rodgersia), Spiderwort (Tradescantia), Astilbes, many hardy Ferns, Sedges, Joe Pye Weed (Eupatorium), Queen of the Prairie (Filipendula), Obedient Plant (Physostegia), Culver’s Root (Veronicastrum), Tall Ironweed (Vernonia). Oh, did I happen to mention Sedges? Three years of trialing them in the “delta” area of my garden and they’re ironclad. I’m a believer.
This is my third year growing tomatoes, but operating from the you-can-never-know-too-much-about gardening school of thought I’d love any tips you could share to give them the very best chance for success. Thanks in advance.
- When plants are established and first flower buds are evident, remove all the “suckers” (the little “extra” shoots between the main stem and the side branches) to direct energy from the lower portion of the plant to the fruiting sites.
- Avoid excessive applications of high nitrogen (the first number in a fertilizer analysis- ex: 15-10-15). High nitrogen will encourage lots of foliar growth at the expense of flowers, and therefore fruit.
- Mulch your plants and make sure you water deeply, but “infrequently”. In other words, don’t let them wilt to get your attention to water, but also don’t flood them every day. Relatively even soil moisture in summer heat will produce best crops ‘cause the root systems have had to work a bit for water, so they’re stronger.
- Avoiding feast-or-famine watering will reduce the likelihood of “blossom end rot” (along with ample supplies of soil calcium). Make sure your veg fertilizer contains calcium (ex: Dr. Earth® Tomato, Vegetable & Herb Fertilizer and Espoma® Tomato-Tone).
- As late Sept. arrives don’t let tomatoes waste energy trying to grow new stems and flowers that will never yield anything. Cut off long shoots above where you can see the newest fruit developing.
I understand the importance of deadheading annuals since most have the potential to re-bloom, and even those perennials that can re-bloom, after their first flower flush. But aside from aesthetics, do I really have to deadhead perennials?
- As a parent may have said to you, you don’t have to do anything if you don’t want to. But do you want the best garden you can have? Okay, putting aesthetics aside (important as they are to the enjoyment of a garden) here a few reasons to keep up with the deadheading of perennials that only bloom once a year:
- Disease. Big, blowsy flowers like spent peonies can contract fungal diseases like Botrytis in humid weather. This can affect the health (and appearance) of the rest of the plant…. and maybe spread.
- Prevents self-seeding of plants with high reproductive potential, reducing future weeding of unwanted seedlings.
- Allowing that plant to go into seed production can still lessen/weaken next year’s flower potential when lots of energy is wasted on seed formation, rather than storing it for a big show of future flowers.
- And I’m not mentioning aesthetics again.
I’m getting excited about the reality of actually harvesting herbs from my own garden? If you were to condense harvesting down to one general point, what would that be?
Harvest herbs when they’re dry (wait until after morning dew has evaporated). Morning harvest is better than dusk as the essential oils are at their peak after cooler night temperatures.
I have a screen of about a dozen Arrowwood Viburnums and I noticed that at the end of last month they were looking a bit, oh, let’s call it ragged. And now just a week or so later the leaves are skeletonized right to the veins. They look like lace. Is this Viburnum Leaf Beetle? Will they kill my plants if I don’t control them?
The answers are yes and yes if the plants are defoliated completely two years in a row. The thing that makes this insect unusual is the fact that both the immature stage (the larvae) and the adult beetles feed on the plants. Devastating. I won’t bore you with the entomological life cycle – that’s certainly Google-able if you’re interested.
Courses of action:
- Avoid the most susceptible Viburnums – Arrowwood and the Cranberry- bush types. Plant the most resistant: Judd (Koreanspice) and Doublefile. The Cornell University website has a very comprehensive list of susceptible / resistant varieties / species.
- The eggs for the 2021 season will generally be laid in current season’s stems (or newest growth, if you will). They will winter over that way before hatching in spring. (Our first samples arrived from customers’ in late May). So, checking for the small, but obvious holes in those stems and pruning out will reduce the start-up population in the spring.
- Encourage beneficial insects like lady beetles, immature lacewings and spined soldier bug that are now known to feed on them.
- Earth-friendly controls like Spinosad (soil-derived bacterium) or insecticidal soap will affect control- BUT must come in direct contact with the insect to work, which can be difficult if they’re feeding on the underside of the leaf.
- Long-lasting systemic controls can also be employed.
I’ve got a two-part question. What happened to my Hostas all of a sudden? And what happened to my dwarf Ginkgo? Both look like heck and it seemed to happen concurrently and almost overnight in early May.
Remember that Friday night when all of our local weather anchors predicted below freezing temperatures? Well, they were right. And the things that I saw most affected in my garden were those two plants. Both were in rapid growth with very soft cell tissue that literally froze overnight. With the Hosta the varieties that were out in the open (and not afforded the protection of structures or overhanging trees) I’m seeing that now a few weeks later the embryonic crowns that were down in the center of the plant and protected have now grown out and the plants are looking good, although maybe a tad smaller than they might have been if those early leaves hadn’t been lost.
There is one other situation going on simultaneously with Hosta and that’s a fungal disease called Anthracnose that is devastating a couple of older species that are particularly susceptible. The fungi cause large, irregular whitish/brown lesions with dark halos around them. The disease tissue dies, cells drop out and the plants are very “torn-looking and ragged”. If this has been an issue now the last 1-3 wet springs then you may want to consider replacing the susceptible varieties with resistant ones. If it’s becoming an historical problem check with us for fungicide recommendations, but those must be used preventatively, not curatively.
As for the Ginkgo, it’s a wait for consistent warmer temperatures to see how they bounce back from the freeze damage they sustained.
I don’t want to even think about how bad the weeds are going to be in my garden with all this rain….and to be honest, I let things go starting last August. What are some of the non-chemical strategies I can employ in my garden (not my lawn) to deter weeds in the future?
That’s a really timely question.
- If you really have an overwhelming amount prioritize and pull any weed that’s getting ready to flower. Once a weed starts setting new seed and releasing it you just added exponentially to the future problem- for years!
- Don’t just break a weed off- that’s not weeding. They’ll come right ba-a-ck. Get it out by the root.
- After you’ve attacked the blooming weeds I always like to set a goal and get one area clean at a time. It’s not only efficient, but gives you a sense of accomplishment when you see a beautiful weed-free area.
- Once an area is weed-free, consider using a pre-emergent herbicide (there are organic and synthetic formulations) to reduce germination. Mother Nature hates bare soil. Mulch, mulch, mulch to reduce weeds. With all the other benefits of mulch weed control is just one more return on your labor investment.
- Plant closer than recommended (especially in veggie gardens where things may be in rows). Shaded soil and increased root competition from your desired plants will reduce weed germination.
- If you’re giving supplemental water realize that a soaker hose or drip irrigation line delivers water to a much more directed area. The areas that are left dry are less likely to support weed growth. Irrigation systems moisten all the soil in an area, encouraging uniform weed germination throughout bare areas.
Aside from watering less often with all this rain there must be other considerations I should be thinking about for my hanging baskets and containers, but I’m not sure what those might be. My entire garden is containers so there’s a lot riding on doing this right. Help?
Got it, okay.
- First thing is to make sure saucers are always emptied. And remember to tip and drain those clip-on saucers that are attached to many plastic hanging baskets. Plants (except aquatics) must never stand in water for more than 30 minutes. For now I’ve removed saucers, turned them upside down, placed the pots back on top of them so they don’t hold water. Succulents really appreciate this. Depending upon the surface your containers are resting on maybe everything doesn’t require a saucer.
- If the latter is an issue, buy “pot feet” to allow drainage so the pot is standing above and not “staining” a good surface.
- Regardless of what the ads for potting soil say about “fertilizer added” it’s not much. With all this rain lots of the nutrients you’ve provided have drained right out of the bottom of the pot. Make sure that you’re fertilizing regularly to replace any leached nutrients and minerals. If you don’t you might start seeing deficiencies, particularly nitrogen, which leaches readily.
- Keep up with dead leaf and flower removal. If anything starts getting blackened, soft, mushy at the base remove and replace before it potentially infects other plants.
When can I safely prune my: Yews, Junipers, Arborvitae and Boxwood?
There’s a range of freedom in a right answer for this question. In a perfect world the aforementioned plants would be happiest if we waited until the current flush (of more brightly colored) growth had hardened off. That is, starts darkening so it resembles the color of last year’s growth. Once that has happened the new growth has started paying the plant back for the energy resources expended. Note: Pruning can be done earlier with no real harm, I assure you.
But here’s where the rubber meets the road- and I’ll admit I do it myself. In a perfect world we would only remove about half of the new growth, meaning the plant is still growing in height and width each year.
That’s fine when the plant is young and we’re wanting it to grow, but what about the established plant that is already over the sidewalk, above the windowsill, pushing beyond its space limits? That’s way more problematic. Down and dirty, when we keep pruning evergreens back to exactly the same same size every year to make them fit their allocated space they continue to drop a year of older needles in toward the center. Still clear? After years and years of this pruning protocol they’re a very hollow core with a thin covering of needles around the top, sides and edges. That makes for a weakened plant.
With yews and boxwood you can soften that pruning blow by reaching in and cutting back a branch to bare wood every once in a while to force an amount of vigorous new internal growth. With Arborvitae and Junipers they don’t have dormant buds back on bare shoots so don’t prune all foliage tips off to a woody stem or that’s what you’ll always have - a bare stem. I think that’s enough to digest, don’t you?
The last few years some of my roses go from picture perfect foliage to skeletonized, and/or with big holes in the leaf. This is way before July 4th so I know it has nothing to do with Japanese Beetle. Guidance here, please?
You’re so right, this has nothing to do with Japanese Beetle and everything to do with two insects that tend to show up concurrently- the rose sawfly and the bristly rose slug. The rose sawfly larvae eat from the underside of the leaf giving it a dust gray, skeletonized appearance. Holes or notches along the edges are a result of the female laying her eggs there.
The bristly rose slug also feeds from the underside so for all practical purposes it doesn’t’ matter really which one did what because they’re very often found together destroying your beautiful roses and they’re controlled the same way.
- Like Japanese Beetle, if you have the stomach for it, they can be hand- picked and disposed of in a container of soapy water or by finger force (use your imagination here). But wear your glasses, they’re small and blend into the rose foliage well.
- Well-aimed, forceful sprays of water will dislodge them from the plant and end their reign of feeding terror.
- Contact and systemic controls are also effective.
Is there some sort of general rule for when to prune flowering shrubs? My “landscaper” pruned my lilacs in September last year and, of course, I have no flowers this year.
There is. If the shrub flowers before July 1 it’s considered spring-flowering and is blooming on the growth that it made the previous summer and fall. Therefore any pruning should be done after flowering (preferably within a month). This allows the shrub time to grow throughout the summer and initiate flower buds for next year.
Conversely, if it flowers after July 1 it’s considered summer-flowering and is blooming on the growth it made in the spring. So, those summer-bloomers can be pruned in late winter / early spring and will still produce flowers the same year from spring growth!
When can I safely plant frost-tender annuals, veggies and herbs?
Year after year this is the most asked spring garden question. And it’s so valid to get the right answer as many box stores, groceries, and others that jump into plant selling for the spring season confuse the issue by offering frost-susceptible plants long before it’s safe to put them out.
The average frost-free date for our area is about May 15. If you wait until that date your chances of having to run out and cover tender plants are dramatically reduced. What are some of the most sensitive plants? Tomatoes (this is the one people are always anxious to get growing to have first tomato bragging rights), peppers, vine crops (squash, cukes, melons), and basil for edibles. Annuals: impatiens, begonias, coleus, caladiums, dahlias, flowering vinca, marigolds, salvia.
For those of you that challenge this advice and plant anyway do understand that even if they aren’t directly frosted if the soil is cold and wet these plants aren’t growing. They’re sitting and sulking. So, you really haven’t gained a thing by pushing the season. At Chalet we don’t have covered selling space. If we don’t have it out for sale that’s our way of telling you we don’t think it’s safe to plant yet.
What annuals are best for partial shade?
Flowering annuals that fill that bill include: all types of begonias, New Guinea impatiens, ‘Beacon’ impatiens, torenia, browallia, fuchsia and streptocarpus. For wonderful foliage effect that will brighten up shady areas of your patio consider coleus and caladiums.
What are ‘Beacon’ impatiens?
Many years (so long ago that I’ve honestly lost track) we chose to stop offering “standard” impatiens, due to a fungal disease, Impatiens Downy Mildew, that wrought complete devastation. The larger-flowered, colored-leaved New Guinea impatiens (NGI) are a different species that showed great resistance to the plague. But people missed the green-leaved impatiens that they used to plant by the hundreds to enlighten their shaded gardens.
Well, through diligence and very focused breeding several of the world’s largest seed companies have brought those long-missed favorites back to us. By using NGI as parents in the breeding work they were able to introduce “high” mildew resistance into the ‘Beacons’. Hallelujah- at last light at the end of the Downy Mildew tunnel!
They were available on a limited basis last year so a number of Chalet employees trialed them in our home gardens. We wanted to test them in: containers, beds, sun, shade, the whole gamut. And they came through like champs for all 9 of us. So, when we recommend ‘Beacons’ we’re speaking from a place of experience and confidence. For 2020, the color selection is: white, red, orange, coral, violet and mixed. ‘Beacon’ impatiens really do work!
Which annuals will give me color all season long?
Almost all of the frost-tender annuals will fill that bill, stopped by the first killing frost in late September/early October. The frost-hardy annuals (pansies, violas, stocks, Ranunculus) that do so well in the chill of spring tend to languish and pass on in summer heat. Understand that when it stays above 90° F. for days on end (and no relief when nights are in the 80s), even the “summer” annuals may “heat stall”. Stalling is simply the plant responding to weather stress, conserving resources by shutting down flower production to survive, waiting to resume flowering when stress conditions have eased.
What if I was naughty, didn’t heed your advice and went ahead and planted frost-tender things well ahead of May 15th and a hard frost is predicted? What should I do?
If things are in containers and can be moved into garages, breezeways, any covered area to keep frost off the plants that’s usually fine. And, we’re talking frost here, not temps in the 20s. Our weather anchors will generally delineate between pockets of possible frost and an area-wide killing frost. With the former, often just putting the container against the house with an overhang will be sufficient protection.
Things already planted in the garden? Get heavy duty stakes (or supports of some kind) and tent sheets, cloth or canvas tarps, or light blankets over the top. The idea is to keep the ambient soil warmth trapped around the plants so frost doesn’t freeze the tissue. Don’t use plastic, especially if it could touch the plants. Plastic isn’t satisfactory.
Frost sidebar: Things to watch for in early to mid-May are: when does the full moon fall? The full moon in the first part of May can often be associated with frost. If there’s a full moon, we have a perfectly cloud-less night with no wind and rapidly dropping afternoon temps, that combination often means frost!
Like everyone else, it would appear, I’m totally addicted to dinner plate dahlias now. Last year was my first year and I’m hooked. I had so many cut flowers late summer until frost it was crazy. Going to do more this year. When is it safe to plant them?
Dahlias are tropical tubers (bulb-like structures that are actually modified roots), so they detest cold, wet soils. I usually plant mine the latter half of May when soil temps are at least 60° F. and a bit on the dry side. In heavy clay soils don’t plant the 6” deep most instructions call for. 4” is fine in clay. Put your stake in the ground when you’re placing the tuber so you don’t drive it through the tuber later and dash your dahlia dreams for the season. The other thing is, don’t water dahlias after planting until the first sprouts break through the ground. They’ll rot easily if you water water water and they haven’t started forming roots and growing.
I’m feeling good that I did my late winter/early spring Hydrangea pruning correctly. But the April FAQs didn’t talk about fertilizing. What should I be doing?
The smooth Hydrangeas (like ‘Annabelle’ and ‘Incrediball”) and the panicle types (‘Little Lime’, ‘Vanilla Strawberry’, ‘Bobo’) will be perfectly happy with one to two applications, of a balanced fertilized like Holly-Tone four to six weeks apart.
The pink/blue mopheads (‘Twist-n-Shout’, ‘Endless Summer’, ‘Bloomstruck’ and my now favorite ‘Summer Crush’) are much more responsive to fertilizer than the others. These macrophylla types must be fed to really perform. Avoid high
nitrogen fertilizers that are apt to push lush foliage at the expense of flowers. Instead go for higher phosphorous fertilizers that will promote bloom. Great examples of the latter would be Dr. Earth’s: Bud & Bloom Booster (3-9-4) or Bulb Food (3-14-2). I put the first application down when I finish spring pruning and the second app on four to six weeks later.
It seemed like the prolonged cool weather last spring made everyone’s bulb flowers last so long it was wonderful. So, I added a lot more bulbs this year. Would you refresh my memory on the aftercare to promote best future flowering?
Of course. The large-flowered things like the daffodils, tulips and hyacinths will really benefit from deadheading. It’s exactly the same as annuals. When you remove the spent flower the energy that was would have been “wasted” trying to make seed is instead diverted into building up bulb reserves for more and/or better flowering the following year.
You could do it with the minor bulbs, such as snowdrops, crocus, grape hyacinths, scilla, but it’s v-e-r-y tedious. And isn’t part of the charm of these minors that they seed around and surprise you with larger colonies each year? So, why bother deadheading if the quality and quantity of bloom won’t be dramatically changed whether or not they’re deadheaded?
Deadheading completed, in a perfect world you want to leaf the foliage on (pun intended) until it turns yellow/brown. As long as the foliage is green those leaves are acting like little solar panels gathering energy and storing carbohydrates for a strong show next year. That can often take up to 8 weeks, but it’s worth it. I like to intersperse daffodils in my daylily bed. The daffs come up, make their appearance, and as they’re “ripening” the daylilies are coming on and covering the not-so-pretty yellow daffodil foliage. Yes, daylilies as cover (up) crop.
As I plan my shrub border, I’d love your opinion on what shrubs (not perennials) have the longest season of bloom in our area?
Any Hydrangea (especially if you count the dried flower effect over the winter), shrub roses (especially the ‘Drift’, ‘Flower Carpet’, ‘Easy Elegance’ and
‘Knockout’ series), the newer varieties of Rose-of-Sharon and Weigela.
We’ve been talking about a new tree for our south-facing backyard. How do you differentiate between an ornamental tree and a shade tree?
Shade trees are generally 30’ or larger at maturity, and are grown primarily for the cooling effect of their foliage (fall color is always a nice bonus, too). Ornamental trees are usually in the 10-20’ height range, and are grown for one of more seasons of interest: flowers, berries, interesting bark, and fall color.
The birches and ornamental pears blur that distinction by getting more than 20’ tall, and having seasonal interest in addition to providing shade.
We’re first-time homeowners and are going to do our own lawn maintenance- at least to see how this year goes… How often do you recommend fertilizing your lawn?
If you’re doing four applications there are major holidays that coincide with our recommendation: Tax Day (If you consider that a holiday), Memorial Day (end of May), Labor Day (beginning of September) and Halloween (late October).
I’m looking for 5 sun-loving, rock-hardy, low-maintenance perennials that don’t have to be fed, babied or divided every few years to perform. I want something that, like a fine wine, just gets better and better sitting there. I freely admit my garden plants have to be L-O-W maintenance or they’re toast.
Okay, you’ve made those needs very clear. I do respect your horticultural honesty. Baptisia (False Indigo), peony, any/many Sedums, Perovskia (Russian sage) and hardy Hibiscus should all meet those requirements.
My neighbor bought some ‘Itoh’ hybrid peonies at Chalet a few years ago and I have to admit they’re pretty spectacular. How are they different than my grandmother’s peonies that bloomed at Memorial Day every year for decades with absolutely no care?
Most simply put they’re a newer class of peonies resulting from crossing (woody-stemmed) tree peonies with standard herbaceous (die-to-the-ground-every-year) peonies. Like all good hybrids these intersectionals (the fancy term for these hybrids) exhibit the very best traits of both parents. The ‘Itohs’:
- Bear enormous flowers in color ranges similar, as well as different from the parents. Shades of yellow that you’ll never see in a herbaceous peony.
- Flowers are borne over a longer time period since their shoots don’t always emerge from the ground simultaneously.
- Are great as cut flowers.
- Have strong stems that tend to stay upright without staking or “hooping”.
- Are clothed in foliage that’s very dissected, attractive and disease resistant.
- “Die down” to the ground each fall and grow back to full size each year.
- Get bigger and fuller each year, making a truly ornamental shrub in your garden, even when out of bloom.
I’d love some recommendations for sun perennials that have the l-o-n-g-e-s-t season of bloom in Chicago summers.
With faithful deadheading the following sun-loving perennials can be showy for over a month: Black-Eyed Susan (Rudbeckia), Catmint (Nepeta), Coneflower (Echinacea), Daylily ‘Stella D’Oro’ or the ‘Returns’ series, Sedum, False Sunflower (Heliopsis), and Tickseed (Coreopsis).
There are so many cool new Hydrangeas coming out annually that I’ve built a pretty good collection in my garden. That being said, now that it’s time to prune them I don’t want to make any mistakes. I have an ‘Annabelle’, different paniculatas (‘Limelight’, ‘Vanilla Strawberry’™ and ‘Bobo’®) and a couple of mopheads (‘Summer Crush’® and ‘Bloomstruck’™). Recommendations, please?
The latter half of March and early April are exactly the right time to get that pruning done. Hydrangea pruning is based on whether the plants produce flowers on current season’s growth or last year’s overwintering stems.
- Hydrangea arborescens (ex: ‘Annabelle’, ‘Incrediball’™) flower on current season’s growth. That means on younger plants you may just want to take off last year’s still-hanging-on flowers. On mature shrubs you can cut them back a third of their height, half, or more. If you have an older plant that you want to rejuvenate you can treat it like a perennial and take it back to within 4-8’’ of the ground and it will regrow and bloom, just much later in the season. If you’re growing them in shade and they’ve been a little floppy-sloppy I’d advise not cutting them back more than a third. That way you’ll have last year’s stronger, woodier stems to better support the weighty flowers rather than having all new, soft green stems that aren’t as strong.
- Hydrangea paniculata (ex: ‘Limelight’, ‘Bobo’®, ‘Fire Light’®, all the varieties that have the elongated, cone-shaped flowers) also blooms on current season’s stems, but is slower to grow than H. arborescens so I generally just remove last year’s flowers and round out the top of the plant, removing any wild stems that have grown well beyond the silhouette of the plant. Please DON’T prune them straight across the top. Any pruning should leave them with a rounded outline, exactly the way they would grow naturally.
- H. macrophylla (ex: ‘Summer Crush’®, ‘Bloomstruck’™ and ‘Twist-n-Shout’™) The varieties mentioned are relatively new on the scene and are special because unlike old varieties they have the potential to bloom on both new and old growth. So, you may want to wait a bit on those and see what stems are green and alive after winter and remove only the obviously dead, brown shoots. This gives you the potential for an earlier crop of flowers from last year’s shoots and a later crop from the new shoots arising from the base of the plant. Summary: Prune as minimally as possible because every shoot from last year has the potential to give you flowers! Can’t fail to mention that I think anyone looking for a really good blooming “mophead” (the nickname for the macrophyllas) should put ‘Summer Crush’® on their 2020 shopping list. It’s compact with great deep rose-pink flowers that blooms reliably even after sub-zero temps. Love it!!!
We bought a new house last year, moved in in August and the lawn’s pretty much a disaster with lots of crabgrass. I understand now’s the time to get ahead of that.
The first thing I would advise is to know the enemy and make sure crabgrass is the problem and not another grassy weed like tall fescue, for example. Crabgrass is an annual grassy weed that would have died with the first hard frost last fall and would literally have disappeared over the winter leaving a “bare spot” in the lawn. If you walk your lawn now and find what you think is crabgrass present, then it’s not crabgrass. Crabgrass germinates in the warmer, sunnier areas of your lawn where there are bare spots 3-6” in diameter. It won’t debut until soil (not air) temps are between 55-65° F. at a depth of 1-2”. We will be putting the soil temp on our website home page once we get into April, OR we have inexpensive soil thermometers for sale, OR you can follow the long-standing recommendation to apply your crabgrass preventer (pre-emergent) by the time Forsythia blooms.
- First: Season-long effectiveness of the preventer is directly related to how uniformly the barrier is applied and remains intact. If you have light raking or turf cleanup to do I’d advise doing it first, then applying the pre-emergent so it doesn’t get disturbed by the tines of the rake.
- Second: If overseeding, standard crabgrass preventers don’t recognize the difference between the desirable seed you’re sowing and naughty crabgrass seeds, and will affect germination of both. Not good. So, if your entire lawn needs overseeding ask us about the pre-emergent product with the selective active ingredient that will allow you to overseed and prevent crabgrass. It works!
How soon can I fertilize my trees, shrubs and evergreens? Any particular favorite recommendation?
Espoma’s Tree-Tone (6-3-2) is a good one and the you-can-never-go-wrong-with Espoma Holly-Tone (4-3-4), which we love. The difference would be the former has 50% more nitrogen, which promotes leaf and stem growth, leaf color. It would be great if you’re trying to coax something to grow a bit faster. We LOVE Holly-Tone for its balanced formula that makes all your “woodies” happy and the 5% sulfur is a nice start to acidifying our alkaline soils for rhododendrons, azaleas, hollies, etc. Oh, and that can be applied now that we’re in spring.
When can I safely remove the leaf mulch winter protection mounds from my roses? And what about pruning them safely - when can I do that?
Not having Tom Skilling’s access to great 10 day weather models this one’s always dicey. Once we’re in April and the leaf mulch has thawed enough that you could pull it away from your roses you might consider pulling it off halfway and starting to spread it around the rose bed. By the time we start getting consistent mid-50° highs they’re going to wake up quickly. Certainly, by the time you see tiny pink buds swelling it’s time to have the mulch completely pulled away and spread around for you growing season bed mulch.
Pruning: Shrub roses (Knockout®, Drift®, Flower Carpet® series) should be examined and as the month progresses will show clearer lines of demarcation between brown, dead wood and green canes with swelling buds. I personally subscribe to the school of rose pruning that says when in doubt cut them shorter than leaving them tall. I know, I know. When you leave them taller they bloom earlier and give you a larger plant over the season. On the flip side, cutting them shorter encourages production of more renewal canes from the crown of the plant making a fuller plant, and also removes black spot (fungus) spores that overwinter not only in leaf debris, but in lesions on the stem, too.
Species roses (like the rugosas) that don’t die back much regardless of winter temps can be shortened as needed, generally never more than half their height.
Hybrid teas, grandifloras and floribundas are pruned like the shrub roses, removing dead canes and shortening to live tissue to produce the fullest plant.
Climbers, especially younger ones need minimal pruning. Otherwise, just remove dead tips to a bud or side branch (IF one exists on the cane you’re shortening). On old, woody climbers with lots of heavy stems you may want to think about removing one or two at the base of the plant to encourage totally new shoots that will be more floriferous in the future.
P.S.- Be ready for spring. We offer a pruner sharpening service for under $10 in our Garden Essentials dept. Just drop ‘em off and you’ll get a call when they’re ready. Clean, sharp pruners make all the difference in the world. I use mine so much I have them done every 2 or 3 months, and that includes hand grass shears.
As it gradually warms in April, what can I safely have in my veggie garden that will tolerate really cold nights and frost?
Transplants of broccoli, cabbage, cauliflower, and kale can be put out. In addition to those, start seeding/planting: lettuce, peas, Swiss chard, turnips, carrots, radishes, spinach, beets, parsnips and onion sets.
And let’s not think about basil, rosemary and cilantro until May when the soil and air temps are consistently warm. But plant perennial edibles like rhubarb and asparagus as soon as the soil is workable!
How much should I prune my clematis now?
This one can’t be answered unless we know the variety name. There are three different pruning scenarios and each variety is classified as a Group: 1, 2 or 3 based on when it flowers. But if you’ve no clue what the variety is err on the side of being very, very conservative. Only prune out dead stems and debris when you see obvious signs of spring bud swelling, what’s clearly alive versus what’s clearly dead. Takeaway: If you don’t keep a garden journal or the pot stakes of anything else do it for your clematis. Generally, the label will tell you which group it falls under. Then you can Google clematis pruning, find your variety’s group and prune away with abandon.
While I do use your leaf mulch like crazy there are still areas of my veggie garden that I seed multiple times over the course of the growing season. I understand corn gluten meal is the best organic weed preventer. What do I need to know in advance to be successful with it?
As we look for organic solutions corn gluten meal has come to the forefront as a potential dual purpose pre-emergent weed control and fertilizer. It does indeed provide slow-release nitrogen (from 9-12%). Under optimal conditions it does a nice job of controlling some annual grassy and broadleaf weeds. To be clear, it doesn’t stop them from germinating, but prevents the seedling root from developing and the weed collapses after it germinates.
Here are the conditions that maximize weed prevention results:
- Apply at least 3 weeks before weeds are expected to start germinating
- Apply uniformly and rake lightly into the soil
- Water lightly to make sure it’s under the surface
- Best results are achieved when soil is dry for 7 days after application
It can be used in lawns, too, of course, as a crabgrass preventer, to be strictly organic.
What is the difference between de-thatching and core aerating? Is one better than the other? What’s the best time of year to do either?
This question always concerns me. It indicates that someone has offered to charge you to de-thatch your lawn. De-thatching is when a machine is used to “pull” thatch from your lawn. I love the analogy that one of my colleagues uses- Would you use a steel brush to pull your hair out? Same thing and does nothing to address the reason excessive thatch exists in the first place. When someone tries to sell you de-thatching you’re dealing with someone who doesn’t know best horticultural practice and you should send them on their way. These are often the same people that mound 6” of bark mulch against your trees and shrubs. Chalet does NOT recommend de-thatching! Sorry, but I do feel better getting that off my chest. Too much misinformation being given out...
On a more positive note core aeration is a widely accepted and valuable practice that works to overcome heavy thatch accumulation (> 3/4”). Core aeration employs a heavy duty machine that pulls plugs of soil from the ground and deposits them on the surface. In punching through the accumulated thatch layer oxygen, nutrients and water have a clear path down to the turf root zone. Soil microbes are brought to the surface and placed in better contact to break down the thatch, as well as creating a great bed for introducing new seed and fertilizer.
Overwhelmingly, our landscape division does this in the fall (nature’s optimal time for major lawn renovation). However, in lawns where the thatch has been ignored and is quite thick it might be done in fall first, and then again in spring to try to “catch up and overcome” the density of thatch.
It’s April and I’ve determined that I have a few houseplants that need to be repotted. Haven’t done this before, what should I know?
You’re so right to be doing it now as days are getting appreciably longer, we’re getting more sun and less cloud-filled days. Like us, plants are waking up from winter doldrums. When you say you’ve determined they need to be repotted I generally use the 50% rule. If I slip a plant out of its pot and the soil mass is 50% or more roots it’s time to consider repotting! Things to know:
- Only increase the pot size by 1” (smaller potted plants) and 2” max (larger pots, say 10” or larger diameter)
- Only use functional pots that have drainage holes. Don’t sentence a long-term plant to a decorative, drainage-free container. Depending upon its location either place the functional draining pot in a saucer, or slip it inside a beautiful decorative container. In the latter case be prepared to water the plant in the sink, shower, let it drain and place back inside the decorative planter.
- Know, too, that as plants start sporting new growth in spring it’s time to start feeding with a water soluble fertilizer. I like Dyna-Gro or the Schultz products.
2019 was my first year harvesting red raspberries that I bought from you. It’s so nice to go to your garden and pull them off the bush. I’ve read a lot online re pruning and admit that I’m not sure I understand what I’ve read. Help, please?
I hear you. I always have to stop and think about this as there are summer-bearing (1 crop) and ever-bearing (which produce a fall crop and then another the following summer).
Summer-bearing (ex: ‘Canby’ and ‘Latham’) raspberries are biennial, meaning they produce a stem one year that overwinters, flowers and fruits the next summer, and then die. Simple- this means that every year after flowering is finished you prune out/remove any canes that have fruited. They will be sending out replacement shoots from the base every year so you are only removing (to the ground) those stems that have fruited and died.
Ever-bearing (ex: ‘Heritage’) raspberries are a bit different in that they flower and fruit at the tips of their first year cane in the fall, then die back partially to where they didn’t fruit. That same stem winters over, flowers on the lower portion of that stem in the summer and then dies. Again, every year it’s producing new stems to keep the plant growing.
Two ways to prune ever-bearing raspberries:
1) If you want both crops, leave the stems up that fruited in the fall. The very tip portion that fruited will die over the winter. Thus, when the plants start budding in the spring cut the dead fruiting tip back to where there is live tissue. That cane will flower down the rest of that stem in the summer, then die, at which time it can be cut back to the ground.
2) Some people feel that in hot weather the quality of the summer fruit isn’t what is should be. They prune back the canes to the ground or within 3-4” of ground in the spring and then only have a fall crop. That pruning can be done in spring or fall.
What are the most common mistakes people make when starting veggie and flower seeds at home? I’m a seed-starting novice and would love to avoid these faux pas if I can.
- Don’t start too early, especially for frost-tender plants. Work back from our average frost-free date of May 10. Overwhelmingly the seed packets will give you a start inside “____ weeks before transplanting” recommendation.
- Not giving enough light so the plants are tall, weak-stemmed and stretched.
- Keeping the plants too wet, especially if you have them under a humidity cover.
- Not using clean seed starting trays/containers and/or a sterile potting mix. Never, ever use bagged topsoil or soil from the garden. That’s a recipe for disaster.
Why should I choose hybrid seeds or plants, rather than heirlooms?
This is a case of both having advantages and it depends upon your goals. In a nutshell a hybrid plant is the result of crossing two different parents with desirable characteristics. Flower and vegetable hybrids generally have one or more advantages like: uniformity, improved vigor, higher yields, better disease or pest resistance, larger flowers or fruit, etc. They are either sterile or the seed (if fertile) usually does NOT predictably repeat the desirable traits of the parent so the seed shouldn’t be saved. The breeding cross has to be made by the seed company every year.
Heirlooms are open-pollinated (meaning parentage is unknown), so there can be some variation in the end result, plant or flower form, or fruit. Generally though the seed can be saved from year to year and will tend to retain the desired characteristics fairly closely. With heirloom veggies many people find the broad spectrum of taste and color very appealing. Heirlooms represent preservation of a varied and historic gene pool, too. Be forewarned that the one heirloom disadvantage we experience most often is increased disease susceptibility. Note: Do NOT confuse hybrids, heirlooms and GMOs.
I’m planting a bed of blueberries and doing a group of three Rhododendrons, too. My soil test results last fall showed my soil pH in both areas at/or above 7.5 – so it’s alkaline. I know the blueberries are even less forgiving than the Rhodies about an alkaline soil. How do I start acidifying my soil? In a perfect world we’d know a year in advance (pause here and laugh at that statement) where we were planting acid-loving plants (blueberries, Rhododendrons, azaleas to name a few). That is because the best long-term acidifying agent is sulfur. Incorporated into the soil (either at general label directions or per the amount recommended by your soil test report) soil sulfur is s-l-o-w to drop the pH and I mean really slow, as in months, to show results. But once it starts it lasts much longer than the alternative- aluminum sulphate.
So, incorporate the sulfur liberally throughout the backfill in those beds and be prepared to add it to the soil surface multiple times throughout the year- especially for the blueberries! When these acid-lovers are in the ground and established and you add the sulfur under the drip-line of the plants you must pull the mulch back. That is, the sulfur must be applied directly to the soil surface and watered to go into soil solution. Then you return the mulch over the roots. If you throw sulfur on top of the mulch the organic matter in the mulch will bind it and you’ll get no acidifying reaction.
A number of my spring-flowering bulbs are out of the ground. Should I cover them if it gets well below freezing?
This is such a great question. The spring flowering bulbs all have their own built-in insulation system and their foliage and buds are well prepared by Nature to handle this situation just fine. The tissue of open flowers, however, is far more likely to suffer damage from sub-freezing temps. While it’s one thing to cover and protect short, stocky spring annuals and veggies from frost it’s a little more challenging to construct protection over a bed of 22” tall, brittle-stemmed tulips, especially if snow is part of the equation causing “protection” to sag. If spring bulbs (tulips, daffodils, hyacinths, etc.) have open flowers do your best to tent something over them- something that is not plastic. You’re trying to keep the ambient heat from the soil trapped under the cover and around the plants.
Do I have to wait for warm weather to put grass seed down in the bare spots in my lawn?
Technically no. The seed will sit dormant waiting for soil temperature and moisture to reach optimal levels for germination. The kicker is that the soil (if not frozen) is compacted now and an ideal seed bed would have been loosened to a depth of at least 4” for deep rooting. And even in areas where you’re overseeding into grass it would be better to try and scratch the soil surface thoroughly enough that the seed comes in direct contact with soil.
I have an old ornamental plum that has 4-6” long corky black/brown growths that seem to encase the branches they’re growing on. Everything beyond those growths seemed to be dead. Will it come back and what are those?
It certainly sounds like the fungus “Black knot” which attacks plums and ornamental cherries. The fungus overwinters in these “knots” and starts reinfecting anew after spring rains. The knots enlarge, girdling the twig, killing it.
Control: On a dry day in winter or early spring while the tree is still dormant prune 4-8” below the gall and discard the dead branch and attached gall. Disinfect pruning tools between each cut of an infected branch. Multiple fungicide applications (come in for our recommendation) should be made starting while plums and ornamental cherries are dormant, repeating at 7-10 day intervals through mid-June.
I would like to transplant a group of three Hydrangeas that have been in the ground for two seasons now. I ignored the mature spread and placed them too close together and the quality of the plant shows they’re unhappy. Is late winter a good time to do this?
Late winter/early spring when plants are still fully dormant is always a great time to transplant. Pre-dig the new holes so that they’re ready to accept the plants as quickly as you get them out of the ground. This not only reduces the time outer roots are exposed to the drying effects of air, but should there be a mishap and the root ball doesn’t hold together well the quicker you get the plant back in the ground the better.
When a plant has been established longer than 2-3 years consider root pruning several months in advance (if you have that luxury). Root pruning is simply determining how large a root ball the plant has (and how large you can lift and move safely) and severing the roots to at least a spade or shovel’s depth. Where each of those roots has been severed roots will start proliferating and the plant will rebound from transplant stress more quickly. Don’t forget to use a starter fertilizer and mulch on the new transplants.
While I did pull my annuals last fall I left all the perennials up for winter effect. How early can I cut them down and finish my spring garden cleanup? What’s the downside to doing it now rather than fall?
As soon as the snow melts enough for you to see what you’re doing. Possible disadvantages of waiting ‘til spring are:
- Soil is generally wetter after winter so the likelihood of compacting clay soil by walking on it (frozen or thawed) is greater than fall
- Many succulent stemmed plants (Hostas, for example) are now wet, stringy slime that is no picnic to cut
- Heavy spring rains may really cut into your window of opportunity to do the cutting back
- If it starts warming early and perennials emerge through last year’s stem residue you have to laboriously remove old shoots without damaging new. That’s my textbook definition of T-E-D-I-O-U S and really adds hours to the process.
- If you’re a “bulb person” you have to watch where you’re stepping or sitting while “cleaning up” lest you elephant-foot emerging bulbs…
As directed by your staff I’ve waited until March to do my houseplant repotting. Why, again, did I need to do that?
Let’s be clear that you’re not going to kill anything by repotting it during the winter. It’s just that unless you have a greenhouse, conservatory window, great south or west windows, or a 5-star artificial light set-up most houseplants are going to be maintaining themselves, essentially dormant, during the short, often sun-less days of Chicago winter. So there’s really no need to increase pot size and have them sit doing nothing until they awaken in mid-March!
What are the most cold tolerant veggies for our area? I want to get started as soon as the ground warms, but I also don’t want to be stupid and lose them. One of your staff members once said, “Don’t be the person that plants early and replants often.”
I could easily have been that person. “Box stores” often get plants in well ahead of the window of safety to plant outside. Customers come in and say, “Why don’t you have tomatoes/peppers/whatever in stock? We saw them this week at ____________________.
We’re gardeners and horticulturists. We want you to be successful and enjoy the process. Planting tomatoes outside the first week in April (and I’m not kidding, this has happened) is a guarantee of disastrous results. We will have no tender annual, veggie or herb out for sale before we feel it’s safe for you to have it in the garden.
That being said the following veggies and herbs are very tolerant of frost: Beets, Brussel sprouts, cabbage, carrots, chives, garlic, kale, leeks, onions, parsley, peas, radishes, sage, turnips
I know that the price of roses spikes astronomically for Valentine’s Day. What is a good alternative?
Roses, of course, are absolutely beautiful, but their life expectancy can range from 3-7 days – more than a week would be extremely unusual. A Phalaenopsis (or Moth) orchid can easily last from a month to three or four. The individual flowers last for weeks and weeks, and they bloom sequentially on that long, arching spike. So, from first flower opening to last one finishing is a long, long time. And unlike the rose bouquet that was pitched you can toss the orchid when it’s done or keep it growing to bloom another year. They’re minimal care as they only need indirect light, occasional watering and perhaps monthly fertilizing.
How do you properly clean a bird-feeder?
It’s important that you disinfect your feeder every two-four weeks based on weather and the level of “wing” traffic it’s receiving. It’s not just about looking good, but about keeping the seed fresh (we’ll reject rancid seed, like the old stuff stuck in the bottom) and reducing the possibility of transmitting diseases.
First, wear gloves. Given the type of “residue” on a feeder you should be disinfecting, rather than just washing. The majority of serious birders recommend soaking in a 10% bleach, 90% water bath for at least 3 minutes. Then rinse very thoroughly. Make sure it’s completely dry before you refill. Thanking you in advance, “The Birds”.
Why can't I plant directly into a container that doesn’t have drainage holes?
We strongly urge people not to plant long-term plants directly in those containers. It’s too difficult to gauge correctly whether the plant is desert-dry or floating . Use those containers to mask the green or black plastic growers’ pots. That way you can slip the potted plant out, take it to the sink or shower, water, let it drain and put it back with no fear of under- or overwatering.
If the plant is too bulky to lift make sure the decorative pot is enough larger in diameter that you can at least see the bottom to see when water starts seeping out the drain holes of the inner grower’s pot. You can either put bricks or substantial shims in the bottom to raise the plant up and out of drainage water. Or you can buy a cooking baster and use that to bulb syringe the drainage water out and into a bucket.
TAKEAWAY: Know that any time a root system stands in water for more than 30 minutes it’s losing oxygen and the roots are starting to die. Think of it as “organ failure” for plants.
Can you simplify the basics of terrarium care?
Since glass magnifies the light transmission you want no more than bright, indirect light. Yes, even in the winter, no direct sun. If, for example, you have an area that makes you squint naturally at the brightest part of the day the light is probably too strong. For open containers (that is, no top) water as needed. Closed systems (where there’s a top and it’s basically a recycling chamber) check visually and water lightly when the soil surface looks dry. Avoid excessively hot sites or really any temperature extremes. Fertilizer is rarely, if ever, needed because you don’t want to encourage excessive growth.
For closed terrariums humidity-lovers like ferns, orchids, bromeliads, air plants and carnivorous plants are great subjects. Notice that cacti and succulents aren’t included in the closed terrarium list. If you’ve got a burning desire for them, an open-topped container that dries out and has lower humidity would be a smart choice.
I haven’t done the seed-starting “thing” in years now. Why should I start my own seeds?
Some things we would consider:
- Seeds are already available for sale. What are the unique, unusual varieties that seeds are available for, but the plants you desire probably won’t be?
- Variety is quite new, seeds are available, but plants may not be for a year or more.
- Flowers of certain things may be only available as mixed colors (as plants), but you may want a specific color and seed is available separately for that color.
- You control how the plant was grown. You know how “clean” it is going into your garden.
- You control the timing. You can “back into” when to start the plants so you have them at exactly the time you want to plant them in the garden. This especially true to have young summer transplants of “cool season/ fall crops” where the plants are never available early enough to mature for fall harvest before winter strikes!
I received instruction in your store last fall on forcing hyacinth bulbs. They’ve been in the crisper of my refrigerator since mid-October, with no ethylene-producing fruit or veggies. I was told they needed 10-12 weeks of cold to trigger flowering. By my count it’s 14 weeks and I’m anxious to smell hyacinths. What now?
Good for you. Now pull the bulbs from the crisper (they don’t have to be potted to achieve the required hours of chilling) and pot them. Shallow containers are preferred as the root system will be minimal. Put them bulb-to-bulb, almost touching each other and the rim of the pot. Cram them in, you want a good show. The bulbs may be showing the start of a green shoot in the neck of the bulb which means they’re rarin’ to go. The top of the bulbs should be just below the soil surface. Water thoroughly, place in a cool, dark place for a few weeks while roots start forming.
Water next when you see the foliage/flower buds starting to emerge from the bulb. That means they’ve started rooting. Now you can move them to bright light and a warmer room, watering thoroughly, but sparingly, until they finish flowering. Generally, they’ll be getting lower light and more warmth in your home than outdoors so they usually stretch (meaning they start leaning/falling over). Prepare to perhaps stake them, but to have the fragrance indoors in the winter is well worth it.
I’ve seen lists for houseplants for many different needs- high light, low humidity, etc. I travel a lot and am often gone for weeks at a time. Aside from cacti and succulents, what tropicals are forgiving of drying out very thoroughly between watering?
A good list might include: Cast Iron plant (yes, it is appropriately named), ZZ plant, Yucca, Ponytail Palm and any of the many, many Sanseveiria (commonly called either Mother-In-Law’s Tongue or Snake Plant).
I’m going to be starting seeds indoors. Having never done it before I’m wondering if all those claims about having very clean containers and sterile seed-starting mix are overblown. How would you answer that question?
Those recommendations are absolutely based in fact- not fiction. There are a number of baa-a-a-a-d fungal organisms just waiting to attack innocent little seedlings before they have a chance to grow to the transplant stage. Clean starting media is as important as sanitary containers. So, if you’re going to be reusing old containers follow these steps:
- I prefer plastic to terra cotta as I think the porosity of clay pots makes it more difficult than plastic to scrub clean and get rid of soil residue, salt deposits and disease spores. So, whatever you’re using Step I is to remove all surface soil and gunk with soapy water. Scrub is the operative word. Do your best to make them look like new. Yes, I do save my plastic and try to get second, third and fourth uses out of them rather than send them off to be recycled. Rinse thoroughly removing the soap residue and allow to dry thoroughly.
- Here’s where the recommendations are all over the board. I’ve read recommendations of as little as 2 T. of household bleach per gallon of water all the way up to 2 cups per gallon. The 2 T. recommendation was well substantiated….
- Soak for 15-20 minutes, then rinse thoroughly with water only.
- I’ve always had good results with off-the-shelf seed-starting mixes.
Is it too early to consider dormant pruning?
End of February/early March is a great time to prune a number of plants- but NOT all! At this time of year the food reserves are still stored down in the root system and lowest portions of the plant. Therefore, rejuvenation of many species of old, overgrown deciduous shrubs could be considered at this time with minimal stress to the plant. Even yews (no other evergreens, though) can be pruned back even to bare stems to try and get them fitting in spaces they may have overgrown. There are methods and techniques to do this properly. So, do your research, ask us and don’t make that first cut without a horticulturist’s confirmation and blessing. Remember the “but NOT all” statement above. Like an extreme haircut there’s no going back after the fact.