White Cedar (Thuja occidentalis) Plantation

(Question)

Hi
I live in Caledon east Ontario and I have ordered 350 white cedar trees approximately 1′-2′ tall and will be planting them end of may.
I haven’t planted cedar before and was wondering if you guys can help me with some planting tips. Like how big should the hole be how deep, how far apart from each other as I’m expecting to have them as a privacy fence. Any type of food I should give them during or after planting. How often I need to water them.
Any tips would be greatly appreciated.

 

(Answer)

Thank you for contacting Toronto Master Gardeners.

Planting 350 trees is a huge undertaking and will require attention throughout the summer.

When you receive your trees you will need to ensure they remain well watered until they are put into the ground. You will need to dig a hole no deeper than the root ball of the tree and twice as wide as it is deep. When digging it helps to put the soil you remove onto a tarp so it is easier to back fill the hole once the tree is in place.

When planting trees you should not add any new soil, compost or fertilizers to the hole. You should refill the hole with the soil that is native to the site. If you add any amendments to the soil the trees will not send their roots outwards gaining important structure and stability. If the soil next to the tree is looser and contains extra nutrients the roots will stay growing within the hole and not venture out. Additives may make things look good immediately but two years down the road you will have a tree that is growing poorly and unstable.

When you gently remove the trees from their containers make sure the soil is moist. Look at your root ball and gently loosen the roots with your fingers. You need to ensure that the roots are not growing in a circle from being in the pot. If you do not loosen the roots they will continue spiraling in the hole, potentially girdling the trunk. This can lead to premature loss of the tree a few years after it is planted.

Look for the spot on the trunk where is starts to widen outwards and the roots start branching off. This spot should be at the level of the soil. You should not pile dirt any higher up against the trunk as that can lead to decay. If you are worried the trees may sink a bit plant them a bit shallower. Make sure the roots are pointing out in all directions. If a root breaks do not worry as this encourages further root growth.

Once you are happy with the placement use the native soil to fill in the hole and pat it into place. At this point you should water the tree and add a ring of mulch (4-6 inches deep) around the trunk of the tree. The ring should look more like a doughnut as the mulch should not touch the tree bark. Leave a couple of inches gap between the trunk and the start of the mulch. The mulch will help retain moisture and will slowly break down replenishing the soil and helping it maintain good structure.

You will need to monitor your trees closely throughout the summer. Trees need a deep watering when they dry out. Push your finger down into the soil before watering to see how dry the soil is below the surface. Your trees will thrive better with fewer deep waterings when needed rather than a small amount of water everyday. With the volume of trees you have you may need to look at an irrigation system.

Good luck with your new plantation!