After the first hard winter freeze, put a fresh 3- to 4-inch layer of mulch around your evergreen trees and shrubs. This is also a good practice with perennials and roses.
If snow and ice accumulate on your trees and shrubs, attempt to brush it off gently, rather than shaking the branches, which can cause them to break. If it won’t come off easily, allow it to melt naturally. Should you see any broken branches, remove them as soon as you can, especially with trees. Broken limbs can be dangerous. Also, they tend to heal better from clean cuts instead of ragged wounds.
Although deciduous trees and shrubs usually fare well in changing winter conditions, some maintenance may be necessary. You may need to remove deadwood or prune the interior of your plants to increase air circulation, which can cut down on fungal diseases. If you choose to reshape a tree or shrub, try to maintain its natural shape, and don’t prune away more than one third of its growth, or you could cause more stress than it can handle.
Evergreens can get pretty stressed during winter, especially if there are extended periods of cold, dry weather. Some color fading is natural, so if you see some changes, don’t worry. However, if you notice your evergreen trees or shrubs turning brown, that usually means they are not doing well.
There are some things you need to check on if you have a few days of unseasonably warm weather in the middle of winter. If you have covered any roses with rose cones, you’ll probably want to ventilate them to keep them from building up heat inside. The same goes for coldframes. But don’t forget to close things back up if the temperature drops down again at night.
Warm temperatures followed by hard freezes pose a danger to emerging flower or leaf buds, potentially causing them to shrivel or come off. Even though there is nothing you can do to reverse this once it has occurred, if you keep an eye on your plants throughout the winter, you can at least know what has prevented a particular plant from blooming once spring arrives. And the good thing is that a lot of plants will set secondary leaf buds to replace damaged ones.
Winter storms can damage multistemmed evergreens, such as junipers, yews, and arborvitae, so tying the trunks together can help prevent this.
Some perennials may also need winter maintenance. Mondo grasses and liriope, for example, can be cut back with a mower or string trimmer, as they are quite tough. However, with more delicate plants, such as ferns, be sure not to damage the crowns. And for your personal safety, when dealing with ornamental grasses, wear a long-sleeved shirt to prevent cuts to your skin from the sharp blades.