Just like humans, plants get cold and need protection from frigid temperatures. Evergreen shrubs can withstand flurries, but heavy snow and other hazards of the upcoming season can wreak havoc on these workhorse yard plantings.
While it is a good idea to hold back on water during autumn to allow plants to harden-off for winter, it is essential for shrubs to enter winter with adequate soil moisture. After a few light frosts in fall, irrigate shrubs deeply and apply a layer of mulch to regulate soil moisture and temperature.
Container-grown trees, shrubs, and perennials can also be over-wintered by placing them in a moderately cold location (temperatures from 20 to 45 degrees Fahrenheit) over the winter months such as an unheated structure. The cold temperatures will keep the plants dormant until spring.
Other plants, like trees and shrubs, become dormant, or rest in the winter. Tree and shrubs, along with herbaceous (soft-stemmed) plants live for two years or more and are referred to as perennials. They store their food, or sap, in their roots as mentioned above.
To protect plants from frost, you will need to cover them to keep the moisture from freezing. While an unexpected frost can leave many gardeners scrambling to find anything to cover their tender plants; it is important to use the right materials.
Symptoms of freeze damage include shriveling and browning or blackening of damaged tissue. Damaged growth usually becomes limp. Eventually, damaged or destroyed leaves drop from the tree or shrub. Fortunately, trees and shrubs have the ability to leaf out again if the initial growth is damaged or destroyed.
Winter is usually the best time.
If you live in an area with distinct winters, the time when shrubs have lost their leaves and become dormant is an excellent time to prune them. Without the leaves, you can easily see the branching structure of the shrub and decide what to cut.
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.
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.
Once the cold is over, water your plants with an inch of water to help rehydrate and start the healing process. Water is pulled from the cells when it freezes and your plants need water to help recover.
Even an unheated garage or shed is typically enough to keep tender plants in an above-freezing environment. Potted tropicals and houseplants should move inside even if temperatures don't drop below freezing. Many of these suffer damage even at 40 degrees.
Shrubs are fairly permanent elements of your garden. They are either deciduous, which means they go dormant and lose their leaves in winter, or evergreen, which means they don't go dormant and do retain their foliage all winter.
Find the uppermost point on a twig or branch where you can find green and cut back to there. New growth should start from these points. Even if your plant has brown bark all the way to the ground doesn't guarantee it's dead. Roots may still be alive and the frozen plant sprout at ground-level.
But it's important to know that shrubs do not last forever (even when they're well-cared for). Like other living things, residential plants will eventually begin to die. The average shrub lifespan is typically 10 to 15 years.
Use a soil thermometer! Insert the thermometer down into the soil for a few days in a row. If the soil consistently measures 50° F or higher, it's safe to plant your deciduous tree or shrub.
After “how?", the second most-asked question we get about pruning is “when?” (Or, "Can I prune this now?") The rule of thumb is to prune immediately after bloom for flowering shrubs, in late winter or early spring for non-blooming shrubs (particularly for heavy pruning), and not after mid-August for any shrubs.
Here's what we recommend: Wrap with twine: If heavy snow is in the forecast, bind the branches with twine. Start at the bottom and work your way up in a spiral pattern. The end result is a conical-shaped shrub that won't catch nearly as much snow.
DON'T prune during fall.
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.
With adequate rainfall, established plant species appropriate for our climate typically need little to no supplemental irrigation during the winter. Exceptions to this rule include newly planted trees and shrubs, plants in containers, and periods of unusually dry winter weather.
After stems have been removed down to the ground, the shrub quickly begins to regrow. Flowering shrubs produce more blossoms in following years and shrubs with colorful stems, such as dogwoods, tend to grow back brighter and more colorful after rejuvenation pruning.
Pruning at this time of year will severely weaken the plants. This is disastrous for the plants and all the hard work you did during the year to make your landscape beautiful.
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.
If the soil is dry and the cold front is not preceded by rainfall, water the landscape before the freeze. Watering 24 to 48 hours before the freeze will elevate the night temperatures by 2 degrees. Don't overdo it. A soggy soil is not healthy for plant roots and will create root disease problems down the line.
As winter progresses, the ground freezes and the sun and wind evaporate more water from the leaves or needles than the plant can uptake to replace it, and the plant gradually turns from green to brown, bronze, or even orange or purple.