Trees to Withstand Winter’s Worst
Slow and steady growth wins the race
Bradford pear and Chinese elm have one thing in common: Both develop dense canopies and brittle stems. Just about the time these trees develop an appealing shape and size which takes some 10 to 12 years they begin to fall apart. As we’ve seen, strong winds can cleave large branches and even snap the trunks within a few feet of the base.
Bradford pear is loved for its abundance of white to pink flowers, scarlet red fall foliage and lollipop shape. That same heavy branching is also the root of the problem. Dense canopies resist the wind even during the winter months when branches are bare, putting enormous pressure on the brittle wood. The original planting of Bradford pear in Adelphi, in Prince George’s County survived only 21 years. Losses to high winds began within 15 years after planting.
If you insist on growing Bradford pear, prune away half of the branches within three years of planting. Don’t wait until the tree is big. Such heavy pruning while the plants are young will ease wind flow as they mature.
Chinese elm suffers from the same problems as the Bradford pear. Many municipalities and homeowners have planted Chinese elm as a substitute for American elm, but the species are not the same. American elms survive for generations, while few Chinese elms survive more than a couple of decades.
Instead of Bradford pear, plant Red Hat, Capital or White House pear. Instead of Chinese elm, plant Zelkova. This tree looks more like an American elm than any other species, and it thrives in our climate.
Plant Oaks for Stability, Longevity
Q I live in a neighborhood with a number of mature poplar trees, that have a tendency to topple in high winds. To protect my home, I should remove two of these trees from a median strip between my and my neighbor's driveways. They offer nice shade in the summer, but they have caused some cracking and lifting of the concrete driveway. The median is 20 feet wide. What would you recommend for a fast-growing, stable tree that will not affect the driveway?
Peter Heckman, Annapolis
A All fast-growing trees are weak-wood trees and begin to fall apart early in life. If you want a tree that will not break apart from high winds and ice, plant an oak. If you want that oak to grow fast, prepare the planting area well. This means improving the soil in that median strip, not just the planting hole. Do not plant near the old stumps but between the stumps. Until the old stumps decompose, they will be robbing nutrients from the soil, thus stunting the growth of the newly planted trees. Prepare the planting hole in a diameter eight to 10 times larger than the root ball and start with a tree with a caliper no smaller than two and a half inches. For the species of oak, I would recommend scarlet, southern red or pin oak.
Ask Dr. Gouin your questions at email@example.com. All questions will appear in Bay Weekly. Please include your name and address.