Q: The leaves of several of my shrubs and trees turned dry and brown in last summer’s drought. Is there any hope that they’ll revive next spring? — Mary Margaret Barron, Bel Air, Md.
A: If they are conifers, which is to say evergreens like pines, spruces, hemlocks, and yews, they are almost certainly dead and beyond hope. But maples, oaks, and ash, as well as other shade trees and shrubs that naturally lose their leaves in autumn, stand a better chance of surviving if even the slightest bit of soft green tissue remains in the central stem of the leaf. If all leaves are fully dry and brown, the odds are that these trees are dead, too. Newly planted specimens are most at risk. If you didn’t water them and they turned brown early in the season, you can bet they won’t revive next spring.
There is a simple way to check for life. On a small branch scrape away the bark with a sharp knife. If you can find green tissue just under the bark and the wood is pliable, the limb is still alive. If the wood is brown and brittle, it’s dead. You should check several branches at different places around the tree before giving up on it. If you have even the slightest hope that it’s alive, put away your pruning shears and ax and just wait, at least until spring, before you start cutting things down. If the tree does leaf out again, pamper it through next summer. Lay down a wide circle of a composted mulch to keep lawn grass out of its root zone. Make the mulch 2 to 3 inches deep, and extend the mulched area out as far as the branch tips above. Composted mulch generally provides all the fertilizer a tree will need. Certainly do not provide any supplemental fertilizer until late fall of the following year; the tree is stressed and needs to rest. If it doesn’t rain for a week, try to apply the equivalent of 1 inch of rainfall to the tree per week. (To determine the capacity of your sprinkler system, put a straight-sided container in the path of the water and measure how much time it takes to deliver an inch; then water accordingly.) A season of such care will put a tree or shrub well on its way to full recovery.