How to take care of newly planted tree in clay soil


Hello, I have a couple questions on the care of my newly planted tree, a serviceberry, amelanchier canadensis. I live in the upper east of Toronto, right at the edge of Rouge park. The spot where my young tree (the trunk is only almost 0.5 inches, more like 0.47 inch) is planted is sunny, it gets a minimum of 6 hours of sun. The soil is clay, it seems compacted. The tree was a container tree. I followed a guide that said that I must dig a hole 9 inches longer than the height of the container. Then add about 4 inches of gravel at the bottom and then backfill the hole. The rootball itself should be about 4 inches above ground and covered with mud for extra drainage. Was this the correct way to do it? Now, my main question is, how do I water this very young tree in clay soil? I know new trees need about 10 gallons of water per inch but how often should I water it? Especially since clay soil intensely retains the water and can suffocate the roots or promote disease… How often should I go about watering it? And is the amount of water I said right? I would also like to ask how I can protect this tree during the winter? These are all the questions I have at the moment! Thank you so much for taking the time to read this and provide knowledge.


Thank you for contacting the Toronto Master Gardeners concerning your newly planted Amelanchier canadensis.

I commend you for choosing a native tree to add beauty to your yard. Amelanchier canadensis prefers grows best in well-drained soil in full sun to part shade, and is tolerant of most soil conditions.

Recommendations about planting trees and shrubs are evolving and incorporating new research findings. Past thinking has been to amend the soil before planting, by digging in either inorganic material, such as sand and gravel to loosen “heavy soil” and “improve drainage” or organic material, such as compost, leaf mould or manure to get your plants off to a good start.

Current thinking does not support these approaches. In fact, by adding inorganic materials such as sand or gravel to the bottom of your planting hole, you are in essence creating barriers to the unamended surrounding soil, which reduces the ability of air and water to move through the soil. This can result in a perched water table.

Rocks In Pots: Drainage or Perched Water Table Problem?  states : “The water table is the dividing line separating the unsaturated zone from the saturated zone. The soil is saturated because the pores are filled with water. The area above the water table is the unsaturated zone and is where the plant’s roots have space to grow well. If gravel is added to the bottom of the pot, the perched water table area of saturated soil without aeration is above that in the container, so even less room for the roots to grow and be healthy in. Root rot diseases can be the result of roots remaining in waterlogged soils.” 

There is a wealth of information on our website listing the proper steps for planting a tree. The following information is from one of our archived posts:

“Begin by preparing the hole in the new planting space.  A general recommendation is to create a hole 2-3 times the width of the tree’s root ball, and as deep as the root ball.  The hole should be saucer shaped.  Create a mound in the centre of the hole to support the root crown.  Landscape Ontario’s Tree Planting Guide has a good diagram of what the hole should look like on page 43 Tree planting guide

Conserve the soil you remove when digging the hole to add back when planting. Unless the soil in your new location is of very poor quality, there is no need to add amendments.  Research shows that trees and shrubs planted in the native soil of their planting location will establish roots better and grow more vigorously.  You can read more about this here: Soil amendments.

If you can plant your tree on a cloudy, cooler day or in the early morning or later afternoon, this will help to decrease the stress of hot, scorching sun. Inspect the root ball by hand to look for damaged or defective roots and prune them away.  If the roots are matted together or encircling each other, this is called being pot-bound.  Gently separate and spread the roots out.

Now you can position your tree in the prepared hole.  The tree should sit at the same height in the new hole as it did in the pot.  Ideally, the root flare (where the stem / trunk transitions to the root system), should be at ground level.  Roots transplanted too deeply can suffocate or may circle the stem, called girdling, which will shorten the life of the tree.  Planting above grade level will cause the shrub to try out faster, make it less stable and more prone to frost heaving.

Refill the hole with the native soil you dug out to create it.  When hole is about 2/3 full, water well to help the soil settle and remove air pockets.  Continue to fill the hole and water again.  You may want to apply an organic soil amendment such as compost and then add 2-4 inches (5-10 cm) of organic mulch (e.g., wood chips) around the tree base but at least 6 inches (15 cm) away from the trunk/stem.

Ensure your newly planted tree gets adequate water over the coming months.  This is a key to successful and healthy growth.  Deep infrequent (e.g., weekly) watering is better than brief frequent watering and can be adjusted based on weather conditions.”

Tree staking is also another topic that has seen much debate. Roots not only absorb water and nutrients, but they also anchor the tree in the ground. If the newly planted tree is relatively small with an adequate root ball, there is no need to stake the tree. The only time a tree should be staked is when the root ball cannot support its height or  the tree is exposed to high winds. If a tree must be staked place the stakes no higher than 2/3 the height of the tree. Stake the tree loosely so that it can move in the wind. This will help the tree develop a good trunk taper. For more information on staking refer to Linda Chalker-Scott The Myth of Staking.

Since the tree is newly planted, my recommendation is to dig up the tree, remove the gravel, dig a saucer shaped hole as viewd in Landscape Ontario’s Tree Planting Guide (above), refill the hole with the existing native soil and apply 2-3″ of a coarse mulch such as wood chips, keeping the mulch at least 6″ away from the trunk of the tree.

Good Luck with your newly planted tree.

June23, 2021