Preparing your garden for winter
Putting the garden to bed for the winter is mostly a matter of cleaning up and covering up. As autumn progresses and temperatures drop, those plants that aren't killed outright by frost prepare for dormancy. Clear out the blackened stems and foliage of annual flowers and vegetables to prevent the possibility of their harbouring disease pathogens and insect eggs over the winter. The cool weather is a good time to make a cold frame, dig and box in raised beds, and make general repairs.While it appears as if all activity in the garden has stopped, there's a lot going on under the soil until it freezes. Newly transplanted trees and shrubs, divisions of perennials, and hardy bulbs are all growing roots, drawing on soil nutrients and moisture around them. Earthworms and various microbes in the soil are still processing the organic material they're finding. Most likely, the organic mulch you spread to protect the soil during the summer months has substantially decomposed. It's important to spread new mulch now -- a thicker winter layer -- to protect plants and soil over the winter months. The idea is not so much to keep the soil warm as it is to keep the temperature even. Once the soil is frozen, mulch keeps it frozen. So if you have shade trees, convert the fallen leaves to mulch and use it throughout your property.
WeatherSnow both protects and endangers plants. A good snow cover insulates the soil like a mulch. However, snow piled on evergreen branches weights them down, risking breakage. Knock snow from the bottom branches first, then work upward. This way snow from above will not add weight to the already burdened lower branches. If branches are bowed by ice, don't try to free them. Instead let the ice melt and release them gradually.
It's important to stop fertilizing in late summer in most areas. Make the last feeding of the season two months before you expect the first frost. Also refrain from major pruning, and stop cutting blossoms. This avoids stimulating any more new, tender growth, which will be killed by the first frost anyway.
Remove all old mulch from under and around the roses; it might harbor insect eggs or disease spores from infected fallen leaves. Just before the first hard, or killing, frost of the season, spread fresh mulch of wood chips, shredded bark, or chopped leaves around the base of the plant, extending as far out as the branch tips. Wait until after the ground freezes to spread the mulch if rodents are a problem in the yard. Mice, especially, like to build their nests in mulch. Water the rose well, especially if it's been through a dry summer.
Once the ground freezes, it's time to add more mulch. If you live in an area with relatively mild winters, simply mound the mulch over the plant crown 6 to 12 inches up the canes. This insulates the soil to maintain an even temperature in spite of the normal alternating winter freezes and thaws. This thick mulch is especially important when there is no reliable snow cover to protect plants. If winter temperatures often drop well below zero, build the mount of mulch, then add more material after every freeze to make the mound higher. Eventually the mulch should virtually cover the bush. Sometimes it's easier to enclose the shrub in a cylinder and fill it with mulch.