Caring for New Trees
How to Plant a Tree
- Dig a hole twice as wide as the container and the same depth as the root ball.
- Gently loosen the roots. Ensure no roots are forming a complete circle around the root ball. For trees with dense mats of roots, you may need to make 3-4 vertical cuts about 1 cm deep around the root ball to break up the circling roots.
- Plant the tree so the top of the root ball is flush with the top of the hole.
- Fill the hole with soil. Tamp the soil around the root ball with your heel.
- Fill the remaining space with water.
- Once the water has drained, add soil until flush with the top of the root ball. Do not add soil on top of the root ball.
- Make a ridge of soil around the root ball to help direct water to the roots.
- Place mulch around the tree. Keep mulch 10 cm away from the trunk.
Caring for Your Tree
Water trees immediately after planting with 20 gal (90 L) of water, assuming your tree came in a 10-gallon container. Water your tree slowly to allow water to get deep into the soil. Generally, trees should to be watered twice a week for the first 2 months and weekly for the remainder of the first year. In the second and third years, water twice a month in spring and summer. Water your tree once after it loses its leaves but before the soil freezes to improve winter survival. The type of soil you have will dictate how much water is required. Sandy soil requires more watering than clayey soil. If planting in fall, water approximately once a week to keep the root ball moist. Careful not to overwater your tree as it is trying to harden for winter.
High phosphorous fertilizer, such as bone meal, is recommended at planting time. Nitrogen fertilizer can be applied in the second spring. Do not apply fertilizer directly to roots. Always follow label directions when applying fertilizer – too much can kill your tree.
Staking is only required for tall trees which may not stay vertical on their own. Stake ties should be wide and soft to prevent bark damage, such as old garden hose. The tree should still be able to move slightly as this encourages a strong trunk. Place stakes into undisturbed soil outside the planting hole. Stakes should be removed after two growing seasons.
You may need to prune at planting to promote a strong structure in the tree. Remove any dead, damaged, diseased, or rubbing branches. Remove water sprouts from the trunk and main branches and suckers from the trunk base or roots. For branches that are too large to cut with hand pruners or loppers, first make cuts as shown by arrows 1 and 2 in the diagram to the right. Make a final cut at 3, as close to the outside of the branch collar (A) as possible without cutting into it. A circle of callus will form around correct cuts (B). Prune as little as possible – over pruning is a common problem. Never remove more than 25% of the live wood of a tree in one year. For trees on your own property, light pruning approximately 3-5 years after planting is recommended to ensure a good structure. Especially important is to ensure that your new tree has one central leader. For trees planted on boulevards, the City will perform all necessary pruning.
Avoid these common tree planting and care mistakes to help your new tree grow and be healthy for decades to come.
- Planting grass at the base of the tree. After planting a new tree, many people reseed or sod grass over the root ball of the tree to maintain their lawn. Grass is very competitive and will draw moisture and nutrients from the soil around the tree, stunting the tree’s growth. Grass and other plants should be prevented from growing in an area at least twice the size of the pot the tree came in for at least three years. A layer of organic mulch such as wood chips is best, but permeable mats can also be used. Organic mulch should be about 5-10 cm (2-4”) thick at the time of application and kept about 10 cm (4”) away from the base of the tree to prevent rot.
- Not removing circling roots. It is very important that you loosen the root ball, including the roots at the bottom, and cut away any circling roots. This allows the roots to grow out into the surrounding soil and prevents the tree from eventually choking itself.
- Improper staking. Many trees do not need to be staked, so only use stakes if your tree is in a particularly windy or high traffic area. Be careful to use wide, soft material to attach the tree to the stake to avoid rubbing injury to the bark and check the stakes and ties regularly. Remove the stakes after two years as the tree will have grown enough to be stable on its own.
- Poor placement. Plan long term and give your tree space to grow. Generally, trees should be planted at least 1.5 m away from any hard surface and 5-8 m away from other trees, depending on the mature size of the tree.
- Waiting to plant. Your new tree should be planted as soon as possible. The longer your tree sits in its pot in your yard, the more likely it is to become drought stressed or otherwise damaged. Trees don’t naturally move locations, so minimizing its transition time from the nursery or garden center to its permanent location is best.
For more information, please contact the Parks and Recreation Department.