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Tree Planting 101: Steps you don’t want to get wrong!

With hundreds of trees in the Tagawa Nursery already available, choosing a tree is the easy part. Planting them properly can be another issue. Do it right, and your tree will get off to a great start.  Skip or ignore some of the basic “rules,” and your tree could be doomed.

We put money, time, and energy into our trees. Why not help that tree be the best it can the minute it goes into the ground? Here are some simple but very important steps you can take to make life good for you and your tree.

There’s digging… and there’s digging right

Certified arborist and Tagawa tree expert Mike Landers has helped me with a lot of tree-related videos over the years.

He has some great advice on how to plant a tree, start to finish.  Mike’s first step may be new to a lot of folks. It’s based on the latest recommendations from Colorado State University. He routinely shaves off the outer half-inch or so all the way around the sides of the root ball.  This will help keep the roots from encircling or girdling the base of the trunk.

So why is girdling such a bad thing? When tree roots girdle, they can slowly strangle a tree as the circling roots get bigger and begin to close off the trunk just at the soil line. Shaving off the outermost roots lets them grow outward, not around in circles.

Dig a hole, but what kind of hole?

Generally speaking, create a saucer-shaped planting hole at least twice the width of a tree’s root ball.  Three times wider is even better because it gives the roots closest to the surface much more access to oxygen.  Lack of oxygen is one of the main reasons roots are slow to expand, which holds the tree back. And it’s good to remember that in our Colorado soils, the vast majority of a tree’s roots grow out, not down, making the width of a tree’s planting hole especially critical.

How deep should the planting hole be?

Look for the area at the base of the trunk called the “flare.” This is where the trunk starts to widen out and the root system begins.

Find the first major root, the “primary” root, near the top of the root ball. The planting hole should be just deep enough to allow the beginning of the primary root and the flare to sit two to three inches above the soil line once the tree is in place.

Having the flare clearly visible, and sitting just above the level of the adjacent soil grade, will avoid creating a “bathtub” effect. That’s when excess water collects in the basin and the tree roots begin to drown.

Carefully set the tree into the hole

If the tree comes in a nursery pot, be sure to remove the pot before setting the tree into the hole. Remove at least the top half to two-thirds of any burlap or wire cage used to contain the root ball after it’s set down into the hole. Be very careful as the wire cage or burlap is being removed. Making sure the tree has been very well watered shortly before planting can help keep the root ball from cracking open, which severely damages the roots.

Mike says unless the soil is extremely sandy, don’t amend the backfill with any compost.  Examine the tree from several locations to make sure it’s upright and just the way you want it. Use the soil removed from the hole to backfill. Water deeply once midway through backfilling to help settle the soil around the root ball, then finish filling the hole.  Make sure the flare is still visible and sits just above the adjacent soil line so you’re not creating a “bathtub” effect that could collect water and drown the root ball.

Don’t put any backfill over the root ball itself! Mike says this is a very common mistake, but covering the top of the root ball with soil could deprive the roots of the oxygen they need. Backfill to the outer edge of the root ball, but never over it.

Use the excess soil to create a moat just outside the edges of the root ball. The reservoir can be a big help in slowly and deeply watering the young tree, especially during its first couple of seasons.

Finish up with water and mulch

It can be surprising how long it takes for water to percolate down through the soil to the bottom of the root ball. Young trees can easily need ten gallons of water or more right after planting.  Watering slowly with a trickling hose inside the moat is an excellent approach.

If you’re inclined to water by hand, measure the amount of water your hose puts out over 30 minutes or so. If you use a watering wand as above, you may have to start, stop and then start watering again to give enough time for the water to soak in.

Depending on the size of the tree’s root ball, using a trickling hose could easily take an hour or more to fully hydrate the roots. As with all watering, never guess! You have to know how much water you’re actually putting down!  

And lastly, mulch

Two to four inches of lightweight organic mulch like shredded bark can go over the entire planting hole and root ball if the planting site is in a dry area.  Any mulch over the root ball in wetter locations may keep the soil too moist.  Always keep the mulch at least a few inches away from the trunk itself so the tree’s bark doesn’t stay wet and creates disease problems.

Here is a link to our tree planting handout that is available in store when you purchase a tree, or in our Garden Library on our website

Come wander throughout nursery!

With so many trees already in, and many more still to come, why not take a walk through the Tagawa Nursery and see if there isn’t a tree that would make your yard more enjoyable or welcoming?  Our Nursery crew will be happy to help and inspire you!