By Adrian Higgins
Thursday, March 18, 2010; PG06
Here's a look at some of the most commonly damaged plants, and the way forward.
Magnolias suffered widespread damage from the Feb. 5 storm, but they are able to regenerate in a way that conifers cannot. Remove broken side branches. If the trunk (the leader) is broken, it should be removed with a clean cut above a lateral branch. The uppermost trunk branches, in time, will turn upward and the dominant one will become the new leader. This technique holds for other trees with single trunks.Bradford pears
Notoriously prone to storm breakage, a Bradford pear that has lost a major branch is structurally compromised and best removed by a pro.Eastern red cedars
This native conifer suffered massive damage. Broken side branches can be cleanly removed. Specimens with multiple broken leaders instead of a single trunk are unlikely to regain a natural, healthy look and should be removed.Boxwood
Boxwood took a hit, especially the slow-growing English box. Boxwood that had been correctly pruned before the storm were naturally more open, allowing much of the wet snow to fall through without flattening and breaking the canopy. Damage to a side branch "isn't a big deal," said Lynn Batdorf, curator of the National Arboretum's boxwood collection. "If it's from the top it could be a big deal" because the foliage acts as a parasol in summer and a blanket in winter over the interior stems.
Boxwood is slow-growing, so any holes that have emerged will take several years to fill in with new foliage. Latent buds will erupt on bare stems over two or three years, but it may take 10 years or more for these to form a new branch structure that will fill in the hole.
The decision to keep a plant, thus, is based not only on the amount of damage, but also on your patience, as well as the prominence of the shrub in the landscape. If the boxwood is missing 30 percent of its canopy and is next to the front door, you may want to remove it. If it's not seen every day, you may be willing to allow it to re-form. The speed of repair is linked to the age of the plant; younger plants are more vigorous. Really ancient boxwood, more than a century old, develops a corky bark that doesn't throw up new growth, said Batdorf.Crape myrtles
Though deciduous, tree forms of crape myrtle received widespread damage because of the upright and congested habit of the branches. Multi-stemmed specimens can be salvaged with the correct pruning of broken stems. A specimen with a broken single trunk may be impossible to fix.Azaleas
Tall azaleas were squashed. Flattened branches will spring back, but a common problem now is a break in the Y-shaped crotches of the branches, said Barbara Bullock, curator of the arboretum's azalea collection. All torn or damaged branches should be removed to a point below the destruction. If that leaves a short stub of a stem, remove it entirely.
If the removal of broken branches creates an unnatural lopsided outline, the healthy branches can be reduced in height but should be cut in a way that retains the shrub's natural layering. Pruning now will remove spring flower buds, but there will be enough left to create a good show. The pruning will spur rapid regrowth.Japanese maples
Japanese maples and other weeping specimens may have suffered irreparable damage if the crotch at the top has split. In an effort to preserve a prized specimen, the gardener could attempt to fix the split by drilling a hole through the stems and drawing them together with a small bolt. With luck, the tissue will knit together.Leyland cypress
Leyland cypress has wiry stems and a relatively shallow and small root system that makes it prone to splitting and leaning. The same vigorous growth that makes this conifer useful as a rapid screen makes it weak-wooded. As a rule, these hedges become massive. The blizzard may offer an opportunity to thin a screen or replace it entirely with more suitable evergreens.
-- Adrian Higgins