Every October 1, like clockwork, the phone calls and questions about evergreen needle shedding (especially arborvitae) start coming into Chalet en masse October 1. The understandable concern is, “I have a pile of yellow/rust/brown needles falling from the center of my ______________________ (arborvitae, pine, spruce, fir, yew, hemlock, etc.). They’ve dropped off and are blanketing the ankles of my plants like mulch.”
The needles (or leaves, if you’d rather) of all evergreens have a finite life expectancy that varies from species to species, but is most often 3 years. Know that’s very species-specific and includes not only “needle” evergreens (arborvitae, see above), but broadleaf evergreens (Rhododendron, azaleas, hollies), too.
The concern arises at this time of year as the shedding of the oldest needles/leaves in the interior has begun, and it could understandably be construed that the plant is dying. It ISN’T! So, why’s the plant doing this? As the oldest leaves become “shaded” by outer new growth they aren’t exposed to much sun. Nature wisely asks, “Why should you live on when you’re not photosynthesizing, not contributing much to the growth and general well-being of this plant?” And the response is the plant casts off the oldest needles leaving a leaf-free branch skeleton in the center surrounded by an outer wrap of the most current seasons of growth.
Any evergreen (most often arborvitae and yews) that’s been pruned regularly, grown in lots of sun and are therefore very dense, may cause this interior shedding to be completely hidden from view. This naked state is covered up and may only be noticeable by looking at the base of the plant, or physically parting the branches to expose the nakedness of the shaded interior.
On the other hand, evergreens that are grown naturally with a minimum amount of pruning (pines are an excellent example) and therefore present an open silhouette more readily flaunting their yellowing older needles and cause proportionately more alarm. “It’s dying, it’s dying.” Evergreens that are grown in considerable shade, not much to their liking by the way, will also be more naturally thin and open revealing their shedding secret even when viewed from a distance. As long as the plant is not showing browning or discoloration of the newest growth (outer edges) it’s perfectly fine. I repeat, interior shedding at this time of year is okay, normal, in fact.
Now let me drop one more consideration into this stew to stir the pot even further. This particular little sidebar is directed primarily at arborvitae. Arborvitae produce noticeable cones, shades of green/yellowish as they develop over the summer, maturing to dark brown by now. They are very different, smaller, than pine “cones” we all know. From one year to the next they are produced either sparingly, or in years of “banner” fertility quite noticeably. In those years of biblical fruitfulness, those masses of dark brown cones can give the notion of a plant that’s in trouble.
In fairness, heavy fruiting may be a response to earlier environmental stresses- excessive: heat, drought, winter cold…. Well, you get it, excessive anything. Often a plant’s resources that are diverted to cone production will mean that plant produces less foliage. What exactly am I getting at here? It’s common that a very heavily-coned arborvitae may look thinner through the body because a plant only has so much energy to expend. Something’s got to give, and its often density at the expense of lots of cones. Again, n-o-r-m-a-l.
Does this resonate with what’s going on in your garden right now? If so, I hope it affords you peace of mind that your evergreens, are indeed, not on the brink of death!
Chief Horticulture Officer