Gardening: Conifers an example of warm weather’s lasting damage to plants
In some ways it was nice to have a mild winter. The ground thawed out early and some of us got a jump on the gardening season. However this doesn’t mean we escaped plants damaged by cold.
Remember when the thermometer dropped from the 60s to the 30s with nights into the teens the second week of November?
Up until that point, the fall had been unseasonably warm. We were still experiencing near 70-degree days late into October and our first frost wasn’t until after Nov. 1. Then the bottom of the thermometer fell out and we dropped 25 degrees overnight. Many evergreen trees hadn’t really begun transitioning into dormancy when the cold hit and were damaged. This process normally takes a few weeks to bring the tree to the point where it can tolerate very cold temperatures. During the process the tree withdraws water from its needles and moves sugars into the roots. If water remains in the cells and freezes, it can break cell walls as the ice crystals expand.
As a result, this spring we are seeing a lot of conifers with damage to last year’s needles. The tips are turning yellow and brown as the trees come out of dormancy. Steve McConnell, a forester with Washington State University Spokane County Extension, said this damage is the result of the rapid change in temperature rather than the actual temperatures. The youngest needles were more susceptible because they hadn’t developed the thick cuticle older needles have. It seems to have occurred on trees that were in open areas and more exposed to the weather or were physiologically predisposed to the sudden change.
The good news is that McConnell thinks we won’t see any lasting damage. The trees will naturally shed the brown needles and the new crop of needles will replace the tree’s photosynthesis capacity. His best recommendation is to be patient and give the trees a chance to recover before you prune or remove them.
It is possible we will see damage on other plants besides conifers as they emerge from dormancy. I have seen some roses with blackened canes right down to the graft. A creeping phlox that lived along my garden path for years has died and my peach tree doesn’t show any signs of life yet. I am just going to have to wait and see what happens.
Plant sale and fair Saturday
If you’re wanting to add or replace plants in your garden, the WSU Master Gardener Foundation’s annual Plant Sale and Garden Fair is 9 a.m. to 2 p.m. Saturday at the WSU Spokane County Extension Office, 222 N. Havana St. Admission and parking are free.
There will be hundreds of flowering annuals and perennials plus berry plants, herbs and veggies grown by the Master Gardeners and priced to sell. Several commercial nurseries will be selling specialty plants. Don’t miss the yard sale featuring garden art and garden tools. The Plant Clinic will be staffed by the Master Gardeners who can answer your gardening questions.