Drought Stressed Evergreens

It’s been a tough few years here in the northeast. I won’t re-hash. I’ve talked about it often enough.

But as tough as it’s been on the people who call this region home, it’s been even tougher on our plants. And the plants are finally showing us that they may have had enough.

I started to notice trouble with Eastern white pines (a native plant, incidentally) in early May, after a very dry winter. What’s interesting is that I wasn’t just seeing signs of distress on these plants near streets–as some of the experiment stations were reporting–but I was seeing it all over the place and often several hundred feet back from the road where “winter salt injury” couldn’t possibly be a factor.

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These two trees are in a neighbor’s yard. They are several hundred feet from the road and in a mixed planting of other evergreens and deciduous trees and shrubs. So clearly this is not “salt injury. ”

Here is a “fact sheet” from the University of Massachusetts on the Eastern white pine situation. Even they can’t quite figure out what’s happening, although they have some speculation.

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More recently I am seeing injury to spruces. They’re either dying from the top down or from the bottom up–it scarcely matters really.

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And then of course there are the ground cover junipers. These are often susceptible to blights like juniper twig blight caused by a couple of different fungal diseases (hard to think of fungi in droughts but actually several of them flourish in the heat). This is my juniper horizontalis with twig blight. It’s going to have to be removed.

The Spoiler is in denial.  He thinks the dead parts can just be cut out. If he would like to try, more power to him. This juniper covers about 100 square feet.  It will leave a huge hole in this garden.

So what is going on? Is it just drought? Is it drought, made worse by warmer winters? Does it matter?

Any time a plant is stressed, it is susceptible to disease and pests. Drought is certainly a stressor, and prolonged drought would be an extreme stressor to evergreens, because they can’t shed their leaves the way deciduous trees can.

I have already cut back many of my “drought stressed” (and therefore either browned or diseased) perennials for this season. That will allow them to conserve whatever strength they have left and put it into coming back next year and other years. No point in watering (either supplementally or if we happen to get any rain) diseased or browned plants. Let the water go to the “good” plants that remain.

But with evergreens, they can’t shed their leaves protectively. So what we may be witnessing after several summers of less than ideal moisture is the evergreens that simply can’t cope. This past warmer winter may also have been a stressor for the trees as well.

Time will tell about whether these trees can recover. If not, New England backyards and forests may never be the same.

 

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