We regularly remind our customers that fall is an excellent time to plant. Above-ground growth is slowing down, cooler temperatures reduce water loss, while new roots can continue to develop in soil that is still relatively warm. These conditions are therefore favourable for helping a tree establish after planting.
But does a young tree need care before winter? The answer is yes. Rest assured, however: hardy trees adapted to our climate are biologically prepared to face the cold season. A newly transplanted young tree simply has not yet had time to develop a root system as extensive as that of a tree that has been established for several years. A few simple precautions are therefore worthwhile. Here they are.
1. Keep Watering Until Late Fall
If you remember only one piece of advice, make it this one: keep an eye on water needs until the ground freezes.
While water needs decrease in the fall, those of your newly planted young tree do not disappear altogether. As the above-ground parts gradually enter dormancy, the roots can remain active as long as the soil is warm enough. Adequate soil moisture helps support this activity.
Water also remains essential for cell function and integrity. A tree that enters winter without a water deficit is therefore better prepared to face cold conditions.
Our Fall Watering Tips:
- Water deeply rather than frequently and superficially;
- Take rainfall and soil drainage into account;
- Avoid both overly dry and waterlogged soil;
- Water thoroughly before the ground freezes if the fall has been dry;
- Pay particular attention to conifers and other evergreens, which continue to lose water during the winter.
2. Add Mulch
Mulch serves several purposes and can really help plants through their first winter:
- It helps retain soil moisture;
- It protects the root zone from temperature fluctuations;
- It helps reduce weed growth.
Apply a 5 to 10 cm layer of organic mulch, such as wood chips or bark, over the soil around the tree or shrub. Spread it out rather than piling it against the trunk, and always keep the root collar clear.
3. Avoid Fertilizing
As summer progresses, the tree gradually stops growing. Its new shoots become woody and harden off. Heavy applications of nitrogen late in the season can encourage or prolong the development of tender new growth at the wrong time. This is why it is generally recommended to reduce fertilization of trees and shrubs starting in August.
4. Resist the Urge to Prune in the Fall
In general, it is best to avoid pruning in the fall and allow the tree to continue its natural hardening process before winter.
Pruning in the fall creates wounds just as the tree is gradually entering dormancy. Its natural defence and wound closure processes then become much less active. As a result, late pruning leaves injured tissues exposed to winter conditions until growth resumes in the spring.
Dead, broken, or hazardous branches can, however, be removed as needed.
5. Protect the Trunk from Animals
Voles, mice, hares, cottontail rabbits, deer, and other animals may feed on the bark, twigs, and buds of young trees and shrubs during the winter. While the consequences are generally less serious for a shrub, damage that completely encircles the trunk can seriously compromise the survival of a young tree.
Tree guards, fencing, wire cylinders, or mesh sleeves: all of these physical barriers can be effective. Keep in mind, however, that some animals can travel on top of the snow and reach the bark higher up the trunk. The barrier should therefore be tall enough to fully serve its purpose.
Preventive Tip
Small rodents can find shelter in tall grass. In the fall, one final round of weeding or mowing the grass short around tree trunks can help reduce their presence at the base of young trees.
6. Should You Protect a Young Tree from the Cold?
During its first winter, a newly planted tree may be more vulnerable to certain stresses because its root system has not yet fully colonized the surrounding soil. In very exposed locations, some shelter can certainly be beneficial, but a hardy tree suited to the region where it is planted generally does not need to be completely covered.
In certain situations, winter protection can nevertheless help it make it through the winter without damage:
- The tree is at the limit of its hardiness zone;
- The site is very exposed to wind;
- It is a conifer or an evergreen shrub exposed to wind and sun;
- The tree could be damaged by the weight of freezing rain or heavy snow;
- De-icing salts may reach the tree.
Several types of winter protection can be used, and this is where your DIY skills can come in handy. Avoid wrapping the protection too tightly or excessively bundling the branches like a mummy. A small fence with burlap attached to it can work very well: it acts as a windbreak and allows snow to accumulate around the tree without weighing down the branches, while maintaining good air circulation.
7. Check the Staking Before Winter
If the tree is staked, check that the ties are not rubbing against the bark or becoming too tight. Make sure the trunk still has some freedom of movement.
8. What About Snow? Often a Friend Rather Than a Foe
Snow is an excellent insulator for the soil and roots. Most of the time, it helps protect a young tree rather than harm it. There is therefore no need to clear away the snow around a young tree.
However, avoid blowing or piling heavy snow from snow removal onto the tree. Extra care is also needed along streets and near parking areas, as de-icing salts can damage many plant species.
One Final Check Before Winter
To finish, we have prepared this summary of the main precautions to take to help your young tree through its first winter at home.
Before-Winter Checklist:
☐ The soil is adequately moist
☐ Mulch covers the root zone without touching the trunk
☐ No nitrogen fertilizer is applied
☐ No major pruning is planned
☐ The trunk is protected from rodents if necessary
☐ If the tree is staked, the ties are properly adjusted
☐ Winter protection is installed if the site requires it
☐ The tree is not wrapped like a mummy under several layers of protection
Enjoy the fall!
Article written by Suzanne Simard, horticultural writer and certified horticultural technologist, and Audrey Rondeau, Biol., M. Env., Production and Development Director at Pépinière Vert Forêt, with editorial support from AI.
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