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Protecting trees from weather extremes

A snowy little surprise arrived in Western New York, damaging a few trees and flowering plants. This is not a shock. We almost always see snow in April and May, and sometimes the storms are significant.

We were fortunate. If the winds had pushed the storm a bit north and all the wet snow had fallen on Buffalo and the suburbs, or if the temperatures had dropped enough to create an icy glaze over everything, it could have been a big problem.

Were our landscapes ready? Do we have the right kind of landscaping?

Snow and freezing temperatures in September and October, or April and May, are not unusual and, with weather patterns changing, could become more severe at times. We should prepare our landscapes.

Those who follow good horticultural practices already are prepared for many meteorological swings. Well-tended, site-appropriate plants in good soil always survive best. But for extreme conditions, there is more to do.

>Storm-ready trees: Trees are both victims and troublemakers during storms. Western New Yorkers remember the trees lost and the property damaged after the October Surprise Storm of 2006. But some professional arborists weren't so surprised at the damage. As arborist/educator Tom Draves put it: "You could have walked around any neighborhood and predicted exactly which trees would drop limbs or crack or fall over in a bad storm. Good arboriculture could have prevented a lot of it."

Homeowners typically put more money and time into their lawns and flower gardens than they spend on their huge, old trees. As the arborist pointed out, while extreme weather could take down any tree, the trees that are cared for perform the best in most situations.

If we own old trees, we cut our risks if we have weak limbs removed or braced, if we lighten canopies and if we take out unhealthy trees that will inevitably fall. We should care for aging trees -- proper watering, mulching, soil care and preventing damage to their root systems. We can insist on correct pruning and removing branch stubs to avoid decay. A healthy tree is a storm-ready tree.

If you are choosing trees, or deciding which "free" trees to keep around your property, you are also determining what can happen in future storms. Do not plant any tree close to the house if it is going to grow taller than the roofline. Even small (less than 20-foot) trees should be placed where their branch tips won't rub on the house, unless you hire professionals to prune them regularly.

Trees cool our homes in summer and provide shade over our decks and patios, but plan for the mature tree size and allow the outermost branches to provide that shade. A huge tree canopy directly over the house, with the trunk 6 feet from the foundation, is just a bad plan.

Trees on the west side of the house -- where it's hit by the hot afternoon sun -- are especially helpful for shade, but are also most likely to drop branches or fall onto the house in a windstorm. So place shade trees at a distance and select the species carefully.

Some trees are innately better home landscape trees than others. Stay away from trees that are weak-wooded, that break easily and drop branches, including the ubiquitous silver maple, Siberian and Chinese elms, and some willows.

Any tree with narrow, V-shaped branch crotches (where cracks develop) is a poor bet. When you are choosing trees, look for U-shaped junctures or wide angles, where branches meet the trunk or large branches meet another branch. The U-shape or a wide branch angle signals a stronger attachment to the tree. Your tree choice and placement in relation to the house are two of the most important landscape decisions you can make.

>Flowers in the snow: Timing is everything when it comes to flowering plants. Some of the prettiest ornamental shrubs and small trees -- magnolias, cherries, flowering quince -- blossom just in time for a windstorm, pounding rain or wet snow. Three weeks ago we saw some magnolia flowers turn from pink to brown overnight; this week, more flowering shrubs lost their annual moment of glory. If the freeze didn't get them, the snow and rain did.

Many daffodils also turned to mush or bowed their flower faces down as if in despair after one of the weather events. Clearly some weather extremes damaged fruit crops this season.

So if we know these patterns, what can we do differently?

*Diversify -- always a good thing. Rather than landscape with a row of flowering plums or magnolias (or any one specimen), choose a variety of plants with different bloom (and risk) times.

*Place at-risk landscape plants in sheltered locations and have a weather survival plan. Even if our region has been reassigned a new zone hardiness number (Zone 6a instead of 5), remember the wild extremes. True hardiness isn't just about the lowest winter temperature, but about wind and heavy snow and rapid temperature changes.

Place the redbud, Japanese pieris or Carolina silverbell in a wind-free location on the east side of the house.

*Plant late-blooming bulbs of every species, if you can find them, or at least several varieties of daffodils, tulips and others. My single-cup (poet's) narcissus went brown, while my King Alfred daffodils held firm and looked wonderful for three weeks. Late blooming tulips and camassia haven't even shown up yet and missed the whole thing.

*Keep covers available to protect selected plants or whole gardens at both ends of the growing season. Your storm emergency kit should include baskets, tarps and clothespins or clamps, including large sheets for a vulnerable vegetable or flower garden.

If weather becomes more severe in the years ahead, we will make more radical decisions about where and what we plant. For now, some "just-in-case" landscaping choices can prevent many disappointments.


Sally Cunningham is a garden writer, lecturer and consultant.