Making sure the plants in our gardens come through the winter without damage requires careful planning.
Hopefully the first necessary action — choosing plants that are suited to your growing zone — took place months ago. If you have a lot of zone 3 and 4 plants in your garden and you live in zone 2, you will have to work hard at protecting them from winter injury. Even then, those efforts may not be successful.
The most tender plants should be in sheltered spots, perhaps near a fence or south of a row of trees. Healthy, vigorous plants will come through the winter in much better shape than those under stress their entire lives because they are planted in less than optimum locations.
Evergreens, particularly newly planted ones, are at risk of winter injury.
Winter wind will increase transpiration of moisture from the foliage when the plants cannot replace the lost moisture because the root zone is frozen. Strong winter sunshine can do the same.
Erecting a burlap screen on the southwest side of an evergreen will shade it from the sun and prevent desiccation and sunscald, while a sturdier barrier on the north and west side will protect the tree or shrub from harsh winter wind.
All plants benefit from going into the winter with adequate water around their roots. Wet soil holds more heat than dry soil, so evergreen trees and shrubs and perennials should be watered thoroughly before freeze-up.
Wrapping the trunks of vulnerable trees with burlap offers protection from the sun and will prevent the bark from splitting.
Some people plant tender plants against the south wall of the house, thinking this is the most sheltered spot in the garden. It might be, but the constant freeze-thaw cycle that is created in such a sheltered spot will significantly damage them during the winter.
The goal is to keep the soil at a constant temperature and as high as possible. The best way to accomplish this is to have a good snow cover.
Many gardeners erect snow fences or use branches to catch snow so that deep drifts cover garden plants during the entire winter. This works well if there is significant early snowfall, but the weather often turns cold before there is significant snow cover.
Mulches solve this problem. A thick layer will insulate plants and moderate the changes in soil temperature. This mulch, whether it is dry leaves, straw or another material, must be kept dry to retain its insulating ability.
As a result, such mulches are often covered with a plastic or Styrofoam material. Alternatively, dry leaves can be placed into a large plastic bag and the bag can be placed on the desired plants to offer them winter protection.
Dry soil or peat moss can be mounded over tender plants such as roses. A Styrofoam cone or some other material should be put on top of the mulch to keep it dry and prevent winter wind from blowing it away.
Flax straw works well as mulch because its high oil content allows it to shed water and remain dry during winter. Wire cages can be used to hold mulch in place, but the cages should be covered to keep the mulch dry.
Shrubs and small trees whose branches will be whipped by winter wind should be tied or wrapped with burlap. This not only protects the branches but also prevents cold air from penetrating to the crowns of the plants.
Tender plants such as hydrangeas can be wrapped with burlap and the burlap cylinder filled with a dry mulch to further protect the plants. Perennial borders benefit from having a thick layer of organic mulch tucked in around the plants before freeze-up.
Never leave plants in containers because frost will enter the soil from all sides, and the severe cold will kill them. Offer extra protection to plants located in raised beds or planters for the same reason. If you must leave a plant in its pot, bury the pot up to its rim in the ground and then cover the whole thing with a thick layer of mulch.
Getting our gardens through the winter in good shape involves a bit of extra effort in the fall, but when spring arrives and every plant emerges unscathed from winter’s wrath, you will be glad that you took the time to properly prepare your garden for the winter.
Note: This is Albert Parsons’ last column. We wish to thank him for sharing his horticultural expertise with Western Producer readers.