Harsh winter conditions can be cruel to your prized ornamental
tree or expensive shrub. The following measures can help protect
your investments. You just need a few supplies, some time
and a bit of work.
The Effects of Dehydration
Winter desiccation of trees and shrubs is a primary cause of their poor health during the
growing season. Evergreens, both coniferous and broadleaved, are particularly susceptible
to the effects of drying wind. Unlike deciduous plants, they never lose their leaves or go
completely dormant. They continue to transpire moisture from foliage all winter long. If
they lose moisture above ground and donít have adequate reserves to draw on at root level,
they get winter burn (brown foliage), branch dieback, and brittle branches that are easily
broken in strong wind. New trees and shrubs in your landscape are also prone to drying out
in strong prevailing winds since their newly transplanted roots may not be well established
before winter arrives.
Before putting away your hose for the season, give your trees
and shrubs a good soak. Keep track of autumn rainfall and
check to see that the ground is moist, but not soggy at the
plantís root level (you may need to dig down). During the
winter, top up water reserves by shoveling salt-free snow
off decks and paths onto the ground surrounding trees and
shrubs. Set up snow fences to purposely create snowdrifts
around important specimen plants.
Broadleaved evergreens (rhododendrons, mahonia and holly) growing in exposed locations benefit
from temporary windscreens made of burlap or snow fencing. Think tent rather than overcoat when
making these shelters Ė they are meant to reduce wind velocity hitting the shrubs, not keep them warm.
Ideally, plant trees and shrubs prone to winter burn in natural shelterbelts such as the leeward side
of buildings or hedges.
The Detriments of Salt
Salt damage can kill woody plants in a single season. Road salt is sprayed onto plants by passing cars.
It then leaches into the soil during a thaw. Symptoms include brown foliage and branch dieback.
In locations close to a busy road, try not to plant anything that will stick up above the snowline.
Alternatively, grow salt-tolerant plants like cotoneasters, rugosa roses, or common honey locust
in these areas.
Offer the physical protection of a burlap mummy wrap to trees and shrubs that arenít salt tolerant.
Donít use plastic wraps Ė shrubs will cook inside them on a sunny winterís day. Be sure to remove
wraps as soon as the road-salting season is over and rinse the plants. Water the surrounding ground
to dilute any salt accumulation.
On paths located near your plants, provide pedestrians with traction by using salt alternatives such
as coarse sand, unused kitty litter (the non-clumping kind) or the new salt-free commercial ice melters.