You’re To(o) Mulch

Happy, healthy plants start with the roots and soil care - amending at the time of planting and mulching thereafter. Spring cleanup is a natural time to think about refreshing your organic mulch. Why mulch? What’s the difference between a mulch and an amendment?

At the risk of repeating what you already know, a mulch is anything placed over the soil surface (but NOT against stems or trunks) for the purpose of: reducing weed growth, keeping soil moist, insulating soil from extreme temperatures (both summer and winter), softening the effects of compaction from heavy rains and foot traffic, and beautifying. Of course, mulching also increases organic matter content in soils, driving positive microbial activity in soil, ultimately improving nutrient availability.  

With all these benefits, why would anyone not mulch? I’ve no idea. As for amendments, that is simply a material added into the soil to improve drainage and aeration, enhance organic matter and microbial populations and open/loosen clay soils (for those of you reading that have sandy soils organic matter also helps bind lighter soils, increasing water holding capacity.)

So, mulches and amendments have overlapping benefits – both should be organic in nature, the former applied over the soil surface, an amendment is incorporated into the soil.  

The question that logically follows is: What mulch/amendment should I use for my ______________ (fill in the blank)? My response is that like many gardening questions there’s not a right or wrong answer. There are just personal preferences. What I’m about to share are, of course, my own personal recommendations based on the research I’ve read over the years and what I’ve found works in my garden. I’ll note (M) or (A) after each for mulch or amendment.

Chalet Leaf Mulch

Chalet leaf mulch is the end product from grinding, then composting North Shore leaves. The resulting organic product has slightly “coarse” particle size and beautiful-when-on-the-ground brown color. CLM retains more moisture than coarse wood bark products and naturally contains beneficial soil microbes. I apply it over all my garden beds every year at spring cleanup- that includes herbaceous (soft-stemmed plants like annuals, perennials, veggies) plants as well as woodies (trees and shrubs). After many years of using leaf mulch anywhere I dig now in my h-e-a-v-y clay soil the difference is pretty extraordinary. There are tons of earthworms in every shovelful and the soil is much less compacted. I particularly like leaf mulch for herbaceous plants as it “melts into the soil” over the course of the growing season. It will need topping off/refreshing each year which is perfect for annual and veggie beds, where a long-lasting wood product isn’t a must. (M, A)

Cotton Burr Compost

Cotton Burr Compost is the composted seed, stem and leaf residue of the (gasp!) cotton harvest. It contains nitrogen since the cotton plant is a heavy feeder that really depletes the soil. When dry it is a lighter brown color and it has a smaller particle size than leaf mulch. This may blow a bit until it settles down, but it can be used in planting holes (my preferred recommendation). If you do use it as a mulch near concrete surfaces make sure mulch level isn’t so high that it could wash after heavy rains as the tannins could stain. (A)

Chalet Organic Compost

Chalet organic compost is different from our leaf mulch as its composted leaves, grass clippings and shredded stems. It has a dark soil-like texture (so, small particles) and color. This, too, naturally contains beneficial soil microbes. If bagged when wet it can clot and need to be “crushed” with your hands before using. Like cotton burr compost this would best be used as organic matter incorporated into the soil at planting, or as a dust-thin topdressing for overseeding lawns. (A)

Shredded Hardwood

Shredded hardwood is the go-to mulch for people with long-term crops (read trees and shrubs) that don’t want to replace it annually. Our shredded hardwood is a rich brown color. We do NOT carry color-dyed mulch. It does have fibers so it interlocks and stays in place, rather than floating. Variable, but might have a slightly alkaline pH. Applied 2” deep you should only need to “top it off” once annually, as it doesn’t blow and doesn’t break down quickly. Doesn’t build soil organic matter content. (M)

Shredded Pine Mulch 

Shredded pine might be considered a “specialty” mulch. While it has been screened for consistent size I find that it has a nice mixture of nugget-like little chunks that are great for opening up air spaces (and therefore improving drainage) in heavy clay. It is has other unique benefits. It is the only mulch we carry that: has a slight acidifying effect and has been found to have an innate fungal inhibitor. With that in mind this would be a great candidate for using on acid-loving: blueberries, rhododendrons, azaleas, hollies. In fact, this is part of Chalet’s recommended way of planting rhododendrons and azaleas since they require a highly amended acidic soil and elevated-above-grade planting to maximize drainage in universally dense clay. Could be used on any woodies, though. Caution, you still need to add sulfur at planting and annually for the acid lovers mentioned above even though you’re using the shredded pine. (M,A)

Cedar Mulch

Cedar mulch is a shredded alternative to our hardwood mulch. Some sources credit it with a pleasant fragrance as well as insect repellent properties. Since cedar is relatively “rot-resistant” it does take a long time to break down. This would make it a good solution for woodies for folks who don’t want to replace or “freshen” their mulch frequently. Due to their physical nature both of the shredded barks can interlock and pack to the point where over time they can sometimes resist absorption in a way that leaf mulch never will. Doesn’t build soil organic matter. (M)

Chunk Bark Mulch

Chunk bark mulch is useful for a variety of utilitarian reasons: around woody plants, for paths, dog runs and play areas. Because the three sizes are nuggets, rather than shredded, they tend to have rounded edges that would be less apt to splinter and break skin than shredded bark products. Again, this is not a dyed product. On slopes or areas subject to flowing water all sizes may float/move out of place. (M)

Coverage would be helpful, wouldn’t it? 

A 1 cu. ft. bag covers 6 sq. ft. 2” deep, or a 2 cu. ft. bag covers 12 sq. ft. the same depth. And just remember these recommendations are just that- recommendations. The important thing is to amend at planting and mulch. You are not, I repeat, not going to kill something because you chose one over the other.

Tony Fulmer

Chief Horticulture Officer