Preparing Trees and Shrubs for Winter
Many trees, shrubs and perennials need protection in order to survive the ever changing and always challenging Minnesota winters. Some plants not considered fully cold hardy can experience root damage, dieback or death simply from temperatures colder than they can tolerate. Newly planted or immature thin-barked, deciduous trees (particularly maples and fruit) can experience sunscald. Evergreens, including deciduous evergreens such as boxwood and rhododendrons, can become desiccated (dried out) from the winter wind and sun. They are also particularly susceptible to damage from heavy, wet snow and ice. Plants can experience damage or death from salt used for de-icing. Damage from animals eating most or all of a plant is another common winter problem. Do not become disheartened though, as there are steps you can take to minimize or prevent all of these.
All plants, whether mature or immature, benefit from mulch. This can be an extra few inches of shredded bark or pine needles, shredded leaves or straw. It is best to add this extra mulch after the ground is frozen.
Use tree wrap and tree protectors on immature, thin-barked deciduous tress to help protect them from sunscald and animal damage. Leave your perennials standing through the winter to make your winter garden more interesting and help trap snow around the plant crowns. This snow acts as an insulating blanket, like the additional mulch, to protect your plants.
Burlap can be used to build windscreens or act as “mummy” wrap. This protection can greatly reduce or prevent needle browning and desiccation in evergreens caused by winter sun and wind.
Multi-stemmed deciduous trees, such as birch and serviceberry, and upright evergreens, such as junipers and arborvitae, are prone to breakage from heavy snow and ice. Loosely wrapping multiple trunks with horticultural tape, nylons or strong cloth strips two-thirds of the way up can prevent one or more of these trunks from bending or breaking. Loosely wrapping an entire evergreen in burlap (like a mummy) can prevent breakage and desiccation. Remember to remove the ties, wraps, tree protectors and burlap in the spring.
Continue To Water
It is important to continue to provide your plants with water throughout the fall. Many people incorrectly think that once it gets cold they should quit watering. Plants still need to be watered, but you can do so less frequently as long as you make sure to water deeply to saturate the root zones. After a couple hard freezes, perennials will start to show signs of dormancy by wilting or changing color. Trees and shrubs should be watered until the ground freezes. Continued deep watering is important for root production and growth and necessary to ensure your trees and shrubs are ready for the winter.
In the Future
If this seems like a lot of additional work, you can minimize it in the future by choosing plants suited to your particular location. Unless you are a learned gardener, stick with plants that are hardy in our area, zone 4. (Northern Minnesota is zone 3.) Locate plants based on the light, soil and moisture conditions they prefer. This greatly reduces plant stress, which contributes to a plants inability to tolerate adverse winter conditions. If you live in an area where deer and rabbits are plentiful, try sticking to plants they find less appealing. Plants grown and sold at Gertens are chosen for their winter hardiness, but all young plants need a little extra protection until they get established. Any of our helpful and knowledgeable nursery staff will be glad to help you with your selections.
Check out this great video on end of season tips to protect your plants before the snow flies: