Winter weather in our home area can be rough. It is hard on us, our homes, our cars, our pets and our tempers, and it is also hard on our landscapes. Last winter killed off hundreds of small trees and shrubs; the combination of the abrupt warming in January and the sudden return to the sub-freezing temperatures of February brought many otherwise hardy plants out of dormancy and then shocked them into fatal temperature traumas. Japanese maples, flowering cherries and crabapples, even early flowering Japanese quinces that had been planted in yards 40 years before were killed all over town.
This winter brings another kind of winter damages. The sheer weight of the massive snow load has broken branches in apple trees, split trunks in European birch trees, sheared off foliage of rhododendrons and converted the ruggedly upright arborvitae's into splayed caricatures of themselves.
My phone has been ringing for the last two weeks with people detailing a list of just these injuries to the domestic settings that our community has labored for decades to improve. The list of broken branches and distorted forms is impressive, and the fate of the individual specimens is still unclear until we can evaluate their status in the light of spring, with the soil unfrozen and the stability of the remaining physiques assessed. But some quick action can really help control the damage.
There are a few common responses to the injuries that will lessen any further damages; while no cure exists for the tearing off of limbs or the splitting of branches or trunks, we can do a few things to help ameliorate the conditions. What is required first is a small understanding of the differences between the world of the plants and that of the animals, of the inability of trees or shrubs to truly heal themselves.
Split wood can be concealed by new bark and broken branches can be laid on the ground and still remain connected to the trunks flowering and bearing fruit for decades, but the damages done will never repair themselves. Years later, the original break may be healed over with layers of new tissue, but it is still there, covered over with a apparently whole new skin, and since the connective web of tubes and feeding tissues is all on the outside of the tree or shrub, the transport of carbohydrate and water can continue.
Deep within the tissue of the branch or trunk, the damage is not only still there, it has spread via the agency of wood-rotting microorganisms into other regions of the tree. Decay will grow into and weaken the nearby wood until all oxygen has been cut off by the new bark, and the weakened wood will always be a threat to the integrity of the tree.
It will be tempting to tie up the cracked or split branches and let the bark regrow, but considering the future growth of the affected branches, it is far better to cut off the damaged elements and encourage new growth. Remember to preserve the growth ring of callus tissue that surrounds the juncture of the branch with the trunk, if you cut through it the healing process will be greatly delayed. Cut just outside that thickened ring of bark and it will heal more quickly.
Rhododendrons and azaleas will quickly resprout anywhere on a branch or trunk, so feel confidant that you can repair them. Crabapples, Japanese or vine maples will sprout new branches from buds and grow in the direction the bud faces, so cut back to the nearest bud facing the direction you want the new branch to grow. Spiraeas, potentillas, roses and other multi-stemmed shrubs will grow new branches low on the existing ones, so trimming back as if giving a haircut will cause new growth to be uniform.
The winter weather may keep us from doing the whole job now, but removing the broken branches so the damage is not made worse is a good idea. Cut off the broken branches to lessen the weight on the split area so the bark does not tear down the trunk.
Black asphalt pruning compound or tree seal has been shown to do more damage than good, so don't worry about using them. On large wounds I use latex paint to help keep the oxygen out and delay the onset of decay.
Landscaping and gardening is a pleasure and gives us great satisfaction, and saving a damaged specimen so it regrows healthily is a worthwhile effort, but do not waste your time if the tree or shrub has been split down into the root area, or if the main scaffold branches have been broken off.
There is no moral value to keeping an ugly plant in your garden, so if the result of the damage is so great that it will not recover soon, consider replacing it with a vigorously growing substitute. There are many lovely ornamental or fruiting plants that will do well here. There are also many improvements in disease resistance, early fruiting and flower production, so the loss of an old friend may be an opportunity in disguise.
David Lendrum, with Margaret Tharp, has operated Landscape Alaska for 25 years in Juneau. They design and build landscapes on every scale and have won numerous awards both locally and nationally. They have a weekly call-in show on KINY and can be contacted through their Web site at www.landscapealska.com.
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