Brown Needles on Your Evergreen? It could be winter injury
After average winters, it can be common for evergreens to show what is generally referred to as “winter injury” in late winter or spring. As you might expect after a winter like we’ve had, it can be even more widespread. You might be noticing this now in your own yard and at Minnetrista I’ve noticed it, too.
The phenomenon often affects white pine and can occur on most evergreen species. Species that are native to colder regions expectedly show less damage than species from warmer regions. I’ve seen it on some young spruce this year as well. The needles may be completely brown or have a reddish tint to them.
White Pine showing winter injury
This injury is possible because evergreens continue to transpire and lose water through their needles in the winter, especially on warmer days. If the ground is frozen or droughty, then the plant can’t recover the water loss and the needles die. Strong winter winds can make the problem worse by increasing the rate at which the evergreen loses water and it’s usually most noticeable on evergreens that are highly exposed to these winds.
Golden Mop False Cypress, an evergreen at Minnetrista, doesn’t like to be in high winds, which leads to winter injury every year.
One of the best ways to deal with this injury is to try to avoid it in the first place. To do this, make sure the soil has adequate moisture in it until it freezes. This will make sure the plant will have available moisture when the ground isn’t frozen during the winter and moist ground won’t freeze as thoroughly as dry ground. Mulched trees will fare better as well.
If you are dealing with this, patience is helpful. It might be tempting to trim out the brown but don’t! Luckily even with severely winter injured evergreens, the buds that will supply new needles can survive. It might take a bit of time but normal growth should resume. If growth doesn’t occur as the season progresses then it’s time to prune, but not before you are sure of the extent of damage.
For the rest of the season, maintain adequate moisture and make sure to limit any other stresses that can affect the tree. This will give your evergreen the best chance to recover from its winter injury.
Dustin Stillinger, an ISA Certified Arborist, is the Horticulture manager at Minnetrista overseeing twenty-one acres of ornamental and natural areas. He can be reached at (765) 287-3563 or firstname.lastname@example.org.