“It’s actually really complicated.” -resident arborist/husband
Before planting, I want to give my reminder that if there’s something wrong with your trees, then contact an arborist. Don’t hire a landscaper to check on your trees or prune them. Landscapers are wonderful, but they don’t have the knowledge, skills or licenses to care for trees. Emily Henderson shared her experience of paying her gardener to prune her trees a few years ago (spoiler: he nearly killer her trees) and ruined their back yard. Tree care isn’t cheap, so plan on getting each tree pruned every 5 - 7 years.
One thing you can do to care for your trees and to give them the best chance at a long life is to plant them properly. The best time for you to plant might be the summer, but the best time for trees is in early spring or fall (really any time during dormancy). Following that schedule is best, but I know that’s not always realistic, so do what you can.
Tree and Location Selection
1. Assess the location where you’ll plant the tree.
THIS IS THE MOST IMPORTANT STEP. Trees are particular about moisture, sun, crowding, make up of the soil, climate zone and hardiness (it’s ability to handle cold weather), so even if you follow proper planting procedure your tree could still die. And even if you have the right spot and you follow proper planting procedure, something could happen around your tree’s environment that could kill it. Wah wah. On a positive note, your tree will probably fine.
The most common of these issues is drainage (or lack there of). If your location has too much water, you might see a lot of clay, when it’s dry the dirt will crack, and you’ll probably see puddling in the winter. There are plenty of trees that tolerate poorly drained soil, but it’s not ideal, as these locations typically don’t have enough carbon or nutrients in the soil that trees need to thrive.
You can improve drainage by doing a few things:
install french drains or dry wells
create porous space in the soil and add rocks
raise the height of the space with a planting mound
2. Select appropriate tree for the location.
There are many ways to select a good tree, go to your local nursery, ask your aborist, here are some other resources for tree selection:
Dirr’s Encyclopedia of Trees and Shrubs
Sunset Western Garden Book
Your local Cooperative Extension site (Oregon State’s is great), the even have an app!
Don’t fixate on planting native trees. Your municipality will have suggestions for trees to plant and a list of invasive trees to avoid planting.
3. Choose good tree stock.
Before you go to your local nursery review the following term and images:
Girdling roots: roots that are wrapping around the trunk of the tree above where the roots come out of the tree. (Girdling roots actually strangle the tree, so look for trees and shrubs with a natural looking root flare.)
Root flare is healthy: When wholesale trees are packed for transport to retailers, like your local nursery, they add soil and often cover the root flare which can cause rotting on the trunk and could eventually kill the tree. Dig down and make sure the trunk hasn’t been covered with soil for too long and look for girdling roots or sign of decay. Trees like this are also more prone getting lethal diseases.
Proper root ball to crown ratio: Look for trees with the largest pot in relation to the size of the canopy of the tree. They won’t need as much babying.
Planting
1. Prepare the root ball.
When you buy trees, depending on the age of the tree and the number of times they’ve been transferred, they’ll have burlap, wire, plastic, twine, roots and other debris that need to be removed before you can plant. Trees can be moved by nurseries up to five times before they end up in your yard. You’ll need to remove the tree from the plastic planter (if the tree is big enough you might have to cut it out. Then take a hand trowel knife or hori hori and dig into the root ball to find the debris and remove it carefully until you can see and expose the ends of the original roots. This might take a while and it’s probably the hardest part of planting, but it’s essential to ensuring a long life for your tree.
During this process you need to:
Remove excess soil from around the roots. You don’t need to remove all the soil, just the enough to expose the ends of the roots.
Remove the girdling roots by pruning them back as close to the origin of the root as possible.
Loosen the soil in the root ball so the roots have a little room.
2. Dig the hole.
This is probably the step that causes the most strife in my marriage. We have planted so many trees in our 9 years together and Kyle still micromanages my digging. Dig the hole in the shape of a square (research backs this up) twice the of the root ball. The hole doesn’t need to be deeper than the root ball, just deep enough that when you put the tree in the root flare is at the same height (or slightly higher) than the ground.
3. Place the tree in the hole such that the root collar (top of the highest roots) is ABOVE THE GRADE of the soil.
Planting trees too deep is what keeps arborists in business. It is the number one reason trees get diseases and die. You don’t want the roots of your plants to be covered by dirt or mulch. Turn your tree so the side with the least amount of growth is facing south. If the tree is growing at an angle, face the angle away from south. South is the direction your tree will grow toward, so if it’s at an angle when you plant it, it will correct itself.
4. Fill in the hole with water. (This is called “mudding it in”.)
Fill the hole to the top, it should be a pool of water. You don’t want your roots to be touching air when they go into the ground. This is especially important in the summer.
5. Add topsoil mixed with compost, a calcium source (gypsum) and some of the surrounding soil.
It’s important to give your new tree nutrients while still exposing it to the soil it will be living the rest of it’s live in.
6. Pack the soil in.
Stomp on the soil and pack it in tight. You don’t want any air pockets that could allow water to sit and cause rotting.
7. Mulch around the tree.
Mulch around the tree, but it shouldn’t touch the trunk of the tree.
8. Stake the tree if it’s leggy or has a small root ball.
Use twine and stakes on opposite sides of the tree to prevent it from uprooting or tipping over until it has established roots and it can support itself.
9. Water your tree regularly.
If you’re planting in the summer, it can be helpful to get gator bags to keep your tree healthy. Either way, you need to keep the soil wet enough so that there’s water at least 4 inches below the top of the soil. I recommend watering twice a week for 10 minutes per tree, and more frequently during heat waves. Make sure to water to the width of the canopy of the tree.