Deep water plants before ground freeze, and continue to water during winter months when temperatures remain above freezing but without precipitation, Erect physical windbreaks. Wrap problem plants with burlap or other material to protect from wind and subsequent moisture loss to evergreen shrubs and small trees.
When should I wrap my plants for winter? This Old House landscape contractor Roger Cook suggests to start wrapping your plants in November. If your plants are new, be sure to cover them for the first two years. The older your plants get, the sturdier they become in surviving winters.
Winterizing evergreen trees and shrubs involves protecting them from drying winter winds. To do this, erect a burlap screen on the windy sides of plants (usually the west and north). Drive stakes into soil before it freezes, and come back when temperatures are steadily in the 20s to staple or zip-tie burlap to stakes.
Insulate Roots from Temperature Extremes
Newly planted shrubs and those that are sensitive to cold temperatures in your area need extra protection at the soil level. Snow naturally helps insulate the plant's root zone and moderate soil temperature, but you can't count on a consistent 12-inch layer of white every year.
No matter what type of shrub you have, fall pruning can stimulate late-season growth that may not have enough time to harden. This can weaken and damage the plant—especially if there's an early frost. Instead, wait until winter and trim bushes when the plant is in deep dormancy.
Know Your Plants' Cold Tolerance
Some frost-tender plants need to be covered as soon as the temperature hits 32°F, while others can handle lower temperatures and/or longer freezing periods. You'll need to look up each of your plants to verify its cold tolerance.
Wait until the final frost in your area to prune frost-damaged plants. Ensure that the cold weather has passed for the season because early pruning can prevent the new season's growth from occurring, as pruning stimulates new growth.
Cover with a burlap sack: After wrapping a shrub with twine, encase it in a burlap sack or commercial shrub wrap if cold, high winds are a threat. The burlap weave is wide enough that the plant can breathe, but it keeps the worst of the biting wind at bay. This covering also protects the shrub from browsing deer.
Once the temperatures are consistently above freezing, it's time to remove the protective burlap coverings.
During excessively cold temperatures
It's minor, but it could impact the look of a plant or create a haven for insects and diseases later. Don't prune when the temperature falls below 25°F.
Use stakes or another support to keep the covering from directly touching the plants. Covering plants helps protect them from a freeze because it helps retain heat radiating from the soil and keeps them warm overnight.
You may wonder how to protect plants from frost when they are planted in the ground? One method – which is useful for larger garden plants and shrubs – is to cover them with horticultural fleece. You could use blankets or bubble wrap, too, to create a protective cover.
Answer: Newly emerged tree and shrub foliage is susceptible to damage from below freezing temperatures. The new growth on many trees and shrubs can tolerate temperatures in the low 30s and upper 20s. Freeze damage is most likely when temperatures drop into the middle 20s or below.
Cover With A Burlap Sack
Burlap sacks aren't the prettiest things to look at, but they offer great protection to your shrubs. They provide the best protection against cold, high winds and will even keep deer from getting to your shrubs.
Bed sheets or comforters work best for covering large plants and shrubs. Newspaper can be used on low-growing foliage, but it can often be difficult to get it to stay in place. You can also use old pillowcases, sheets, towels and even cardboard boxes.
Don't Prune in Late Summer and Fall
Pruning shrubs in August or early September may encourage a late flush of growth.
Spring flowering shrubs and trees.
Shrubs and trees like lilacs, azaleas, and others will grow best when they are pruned right after they flower in the spring. Avoid pruning them in the winter as it may stunt their growth.
Don't shear the branches of spring flowering shrubs (Forsythia, Lilac, New Mexico Privet, Spirea, Flowering Quince, and others). These shrubs produce flowers on last year's wood, so removing old growth will reduce or prevent flowering. These plants should be pruned immediately after they are done blooming.
When Should You Cover Plants? Cover your plants at night and remove them during the day when the temperatures rise above 32 degrees F, so that the soil can warm up again.
Cover Plants – Protect plants from all but the hardest freeze (28°F for five hours) by covering them with sheets, towels, blankets, cardboard or a tarp. You can also invert baskets, coolers or any container with a solid bottom over plants. Cover plants before dark to trap warmer air.
Never shear a shrub in fall (or ever, actually, but that's another article) and leave major pruning or renovation for late winter/early spring, or immediately after bloom for spring-flowering shrubs.
Mild fall weather may have you thinking about pruning shrubs and trees. But it's better to wait till late winter, or, at least, after leaves have fallen. Fall isn't the right time to prune trees and shrubs. There are good reasons to wait till late winter or after the plants' leaves have fallen.