Saving Trees That Have Suffered Heat Shock

For weeks, I’ve been worried about a three-stemmed birch tree in our side yard. The leaves have turned yellow and are falling. Oddly, the two other birch trees are healthy. What is the problem? I went to a local nursery (the one that created our landscaping plan) and asked for help.

According to the tree expert, my birch tree isn’t getting enough water. This is surprising because we have a sprinkling system. The tree expert showed a birch tree in a large pot and it looks just like our failing tree. “This tree needs more water,” he explained. Then he showed me two other trees with small green leaves on them.

“Last week these trees were almost bare. A strong wind swept away the dry leaves and now, with extensive watering, they’re growing new leaves,” he said. This nursery uses river birch, he continued, trees require more water than other birch.

The national heat wave has caused many people to worry about their plants, trees and shrubs. KMBC Television in Kansas City, Missouri posted an article on its website, “Heat Shock Suspected as Trees Drop Green Leaves.” Worried residents have been calling the Master Gardener’s Gardening Hotline with questions about sycamore, maple, pine, oak and birch trees.

The article points out that leaf drop often happens when trees transition from cool to hot weather. In extreme heat, the trees struggle to support all of the leaves on their branches. Heat shock isn’t the same as transplant shock, which can happen when a root ball is damaged or a newly planted tree is over-watered.

“The Tulsa World” published an article about heat shock titled “Water Stress.” Extreme heat has caused water usage to soar. If water usage continues to surge a rationing system may be activated. “Mature trees can survive heat shock,” the article notes.

I live in Minnesota, a state with plenty of water and rich soil. Though our three-stemmed birch was getting water, apparently he sprinkler head is too far away to give it enough. I was going to haul out our soaker hose, a hose with tiny holes in it, but nature intervened.

Torrential rains hit the state with such force that many towns lost power. The intersection in front of our house turned into a lake. We live at the bottom of a hill and so much water rushed down the hill that geysers of water shot out of the manhole covers. Water began to creep across the front lawn and I was glad we had flood insurance.

What became of the fragile birch? Like the potted trees at the nursery, the wind blew dry leaves off the tree and new green leaves appeared. We’ve run the sprinkler system several extra times and rain storms have taken care of our watering problem.

To prevent heat shock, make sure your trees get enough water. Use a soaker hose or insert a watering stake at the base of the tree. You may also buy a hose timer, start the hose early in the morning, and set it to turn off while you’re at work. If you’re going on vacation, ask a neighbor to water the tree or trees for you.

Copyright 2011 by Harriet Hodgson

Source by Harriet Hodgson