ISA Certified Arborist PR4633A
Journeyman Landscape Gardener
Qualified Tree Risk Assessor
Article Updated: June 2016
There is something quite special about planting something that will most likely outlive you and become the home for many organisms throughout its life. Planting a new tree is in my consideration one of the most positive ways of contributing to the long term health and sustainability of our urban landscape. However, if not planted correctly your tree may not live up to it’s full potential. Most urban trees die within 8 years of planting.
Tree planting is not overly complicated, however taking a few thoughtful steps prior to planting and ensuring the tree has what it needs in the years following go a long way to creating a healthy specimen that can be enjoyed for years to come.
Before planting, thought should be given to selecting the right tree for the right spot. Mature size, fruit/seed production, and what light, soil and moisture conditions the tree needs should all be considered prior to visiting the garden centre to pick a tree. This will prevent a myriad of problems which can result in the tree outgrowing it’s space, becoming stressed or requiring premature removal.
Once you have selected the right tree for the right spot, you are ready to plant. Following these steps will significantly reduce the transplant stress the tree faces after planting as well as ensuring the tree can begin to establish as soon as possible.
- Find the root flare on the tree trunk. This widening of the trunk at the trees base is where the trunk transitions into the roots. If this is not visible some soil will need to be removed from the top of the rootball to expose it. This flare should be equal to or slightly above the finished grade after planting. The height of the rootball is used to determine the depth of the hole.
- One of my favourite tree quotes is “It is better to plant a $100 tree in a $200 hole than to plant a $200 tree in a $100 hole”. Ensuring that the whole is the correct depth and width is essential to it properly establishing. Start by digging the hole two to three times the width of the rootball. The depth should be equal to the height of the root ball. It is important to loosen the soil surrounding the young roots so they can extend into the new soil. If the hole is too small or the edges are compacted, the roots will just grow in circles inside the hole leading to girdling roots and other major problems. The hole should not be any deeper than the height of the root ball or the roots will have trouble developing due to a lack of oxygen. The number one problem I see with new trees is planting too deep.
- If the tree is in a container, loosen the rootball as much as possible without damaging the major roots. This will help encourage rooting into the soil around the root ball. Place the tree in the hole and be sure that is straight before backfilling. This may require someone viewing from several angles. It is tough to straighten a tree after backfilling has begun and is not possible to do after a tree has been growing at an angle for for than a year or so.
- Backfill the hole by about 1/4 and gently pack the soil around the rootball. If the tree is balled and burlapped then remove the burlap and wire from at least the top third of the rootball. Continue adding soil a few inches at a time and gently but firmly pack the soil so that all the air pockets are eliminated as they will dry out the roots.
- Stake the tree only if required. Most trees will not require staking but on windy sites or with very top heavy trees, it may be necessary. Two stakes should be used on opposite sides of the tree. The material used to attach the tree should be flexible and allow for movement in the wind but catch the tree before it tips over. The material should also be soft to keep from damaging the tree’s bark. The stakes should never be left on longer than 2 years.
- Mulch the area disturbed to dig the hole. This will conserve moisture and buffer soil temperatures. Wood chips work best but many organic mulches are available. This mulch should be 2-4 inches deep but should be kept an inch or two away from the trunk to prevent decay.
- After planting, the soil should be kept moist. Overwatering can cause some problems so generally trees should be watered once a week without rain and more frequently in hot, dry conditions. Pruning should be left for a year or two after planting unless branches were damaged during planting. Too much pruning will deplete energy that the tree needs to get established.
Following these steps will give your tree the best chance to thrive, and as most Calgary gardeners would attest, in our climate they may need as much help as they can get.