Cooler temperatures and increased humidity in autumn reduce stress on plants, helping them to settle comfortably into their new environment. There’s no need to constantly pamper them with watering – the autumn rain takes care of that. The soil, still warm after the summer, stimulates rooting, allowing plants to settle in well before the onset of frost. By spring, your plants will already have a head start on new plantings. What’s more, autumn also means bargains! Nurseries often offer end-of-season discounts, so you can add new beauties to your garden without emptying your wallet.
When Is It Too Late to Plant?
As long as your shovel still penetrates the soil, you can plant, but try to do so at least six weeks before the ground freezes completely. This gives your trees and shrubs time to establish themselves before winter. If you’ve reached the point where you’re scraping snow off the ground to find some soil, it’s clearly too late!
Spring Planting Too
Spring is also a good time to plant, especially if you didn’t have a chance to do so in autumn. But spring is peak season for gardeners. Everyone starts at the same time, and it’s a bit of a race to buy the best plants. You also need to be more attentive, because young plants must not lack water to establish themselves properly, especially if the spring is dry. Keep an eye on them, especially during the heat and drought of summer. The soil is still cold at first, which can slow down rooting a little, but as soon as temperatures rise, the roots grow rapidly.
Some Exceptions
Conifers are particularly susceptible to dehydration during winter because of their persistent needles. Unlike deciduous trees, which shed their leaves in autumn, conifers keep their needles all winter long, which means they continue to lose water through transpiration, even when the ground is frozen and water availability is limited. This is why they need to root well before winter, so they can absorb sufficient water and avoid dehydration. Planting conifers in spring gives them the whole growing season to develop a solid network of roots capable of drawing water from deeper down.
Certain other plants are best planted in spring, notably bare-root trees and shrubs, which are more vulnerable to the rigors of winter. Similarly, species from warmer climates than ours, which are at the limit of their hardiness, often need more warmth to acclimatize before their first Canadian winter. Finally, shallow-rooted trees and shrubs, such as rhododendrons, need to be planted in the spring to root firmly before the onset of frost.
Choosing a Tree or Shrub to Plant
Choosing a tree or shrub for planting is a bit like choosing a good pair of boots for winter: it has to fit the climate, the soil and the space available. First, choose species adapted to your hardiness zone. Don’t dream of a palm tree if you’re in zone 4! Next, check the quality of your soil. Is it heavy and loamy, or rather light and sandy? Choose plants that will naturally thrive in it. Finally, think about the mature size of your future tree or shrub. It’s all very well to want a majestic maple, but if your yard is small, it could become a big problem. And one last lazy trick: go for small specimens. They adapt faster, cost less and in a few years’ time, they’ll have caught up with the big guys!
Planting Trees and Shrubs: The Basic Technique
- Preparation: Water the root ball and planting site 24 hours before starting to moisten the soil and make the work easier. Gather the necessary tools, such as shovels, secateurs, mycorrhizae, etc.
- Positioning: Place the tree or shrub in its future location to check the visual effect. Don’t forget to check its size at maturity to make sure it will have enough room!
- Planting holes: Dig a hole twice as wide as the root ball, but the same depth. Lightly loosen the bottom of the hole, then tamp down with your foot. If the soil is clayey, lightly scrape the sides of the hole to facilitate root extension.
- Checking depth: Place the root ball at the bottom of the hole to check the height. Make sure the collar (the space between the roots and the trunk) is not below ground level. Adjust by adding or removing soil if necessary.
- Plantating:
- For potted trees and shrubs: Start by removing the root ball from the plant by turning the container upside down and tapping the bottom to loosen the root ball. Once the plant is out, check the roots: if they are coiled, notch the rootball on all four sides to direct them outwards. This prevents the roots from continuing to encircle the rootball and smother the plant. Finally, place the shrub in the prepared hole, adjusting the depth if necessary by adding or removing soil.
- For tangled trees and shrubs: Untie and remove the burlap, then place the shrub on a small mound of earth in the center of the hole.
- For bare-root plants: prune off damaged roots, then spread the roots around a mound of earth in the center of the hole.
Mycorrhizae, those little microscopic fungi that team up with your plants’ roots, are probably already present in your soil, especially if it’s healthy. But honestly, it doesn’t hurt to add a little at planting time. To do this, sprinkle a handful of mycorrhizae directly onto the root ball of your tree or shrub. These fungi will help your plants to better absorb water and nutrients.
- Filling the hole: Fill the hole halfway with soil, tamp lightly and water thoroughly. Then complete the filling and water again.
- Forming a trough: Form a trough of earth around the shrub to retain water and facilitate watering, especially on sloping ground.
- Mulch: Spread an 8-10 cm (3-4 inches) layer of organic mulch around the tree or shrub to maintain moisture, protect roots from the cold and reduce weeds.
- Watering: Water generously once more.
Fertilization After Planting
After planting, people often ask whether it’s necessary to fertilize. The short answer: it’s not necessary, unless a soil analysis reveals specific deficiencies. If you’ve added mycorrhizae, they’ll do their job in fetching nutrients.
If you prefer to amend or fertilize, opt for compost or a slow-release organic fertilizer containing phosphorus, which helps roots take root. Simply spread it on the soil, without incorporating it, and let nature make the nutrients available to the plants. Don’t forget to cover the entire area that your plant’s roots will occupy at maturity, not just around the root ball. In other words: feed the soil, not just the plant.
Care After Planting
Once your tree or shrub is in the ground, all that’s left is to give it a little attention so that it settles in well. Firstly, make sure you water generously after planting and continue to do so regularly, especially if it doesn’t rain, for the first year after planting. Even if the weather is cool, roots need water to develop. Water deeply rather than often, to encourage the roots to sink.
Next, apply a good layer of organic mulch around the base. Mulch keeps the soil moist, reduces weeds and protects roots from temperature variations. Don’t put it directly against the trunk, but leave a small gap.
As for stakes, most shrubs and trees don’t need them. However, if you’ve planted a particularly large specimen or one in a windy area, a stake may be useful for the first few seasons. Be sure to secure it firmly, but not too tightly, to allow the plant to sway slightly in the wind, strengthening its roots. Don’t forget to remove the stake once the tree is well rooted, to prevent the branches or trunk from deforming as they grow around the stake.
Finally, don’t rush into pruning. Let the shrub settle in before thinking about shaping it. If you see any dead or damaged branches, remove them, but for the rest, give it time to grow a little before getting out the pruning shears.
This is so different for our climate. I remember comparing our Californian standards to those of Pennsylvania, and making the same realization. Freezing and dehydration are not a concern for us, since winters are mild, but also rainy. We can dig whenever we want to. Here, it is best to wait for the rainy season to start, so that irrigation is unnecessary until the rainy season is over. It ends rather suddenly in spring.