Getting plants through winter cold

Although cool summers are splendid, winters in northern latitudes and high altitudes are often long and cold, so plants grown there must have exceptional hardiness. Here's some tips for getting your plants through the blustery winter months.

Use the hardiness ratings for your locale as a guide when shopping for plants. Also look for protected areas in your yard, called microclimates. Microclimates exist in spaces protected from freezing winds by walls, fences, or dense evergreen planting, and also are places where a masonry wall or rock outcropping may absorb and hold the sun's heat, elevating the surrounding temperatures.

You can use these warm spots to grow plants rated one or two Zones warmer than your area's Zone. (In Canada, there are Zones 0 to 9).

To help garden plants get through freezing winters, use mulches. The insulation provided by a generous layer of mulch placed over the root zones will protect perennials and shrubs from cycles of soil freezing and thawing, which can heave the plants out of the ground, leaving the roots exposed and vulnerable to freezing and dehydration.

Mulching is especially helpful in mild-winter areas where there is no consistent snow cover. The best winter mulches are fluffy organic ones like leaves, hay, straw, and evergreen boughs. If you use leaves chop them with a shredder or lawn mower. The chopped leaves will offer good insulation and are less likely to blow around.

Sometimes plants in cold-winter climates are ready to go into the garden in spring, but the soil remains too clammy and wet for planting. So gardeners face frustrating delays. Building raised beds or berms may give you a head start on the planting season, because they warm up and dry out faster than lower-lying garden areas.

Raising the soil level even 10 centimetres (four inches) can offer the additional advantage of superior drainage for plant roots. Indeed, the combination of great drainage and cool-summer weather brings out the best in several stellar perennials, such as artemisia, catmint, and veronica, which require excellent drainage to reach their full care-free potential.

Peonies and shrubs persist for decades, and their roots should not be disturbed. Leave room between these permanent plantings for growing annuals. In spring, the vacant spaces allotted to summer annuals will give you room to carefully move about, pruning shrubs and removing debris.

• To avoid spring planting delays due to soggy soil, prepare new beds in the fall.
• Mix in organic matter and mineral soil amendments as needed, such as lime (in acidic soil) or garden sulfur (where soil is alkaline).
• Wait until just before the soil is dry enough for planting in spring to add fertilizer.