Ten planting mistakes that quietly kill trees

Number one is planting too deep, and it is the mistake we correct most often. By the time the crown thins out, nobody connects it to a decision made a decade earlier. These are the errors we see over and over, in yards, on commercial sites and in municipal plantings.

Jump to: The seven steps · Too deep · Mulch volcanoes · Burlap and baskets · Circling roots · When to plant

1. Planting too deep

This is the big one. The root flare, where the trunk widens into the first structural roots, must sit at or slightly above the finished grade. Buried flares lead to bark rot, girdling roots and a tree that never gets its footing. Silt mounded against a trunk by a flood does the same to a yard tree; the bottomland species that shrug it off are the subject of how floodplain trees survive high water. If you cannot see the flare on the planted tree, it is too deep.

2. Trusting the nursery soil line

Container and balled trees are very often already too deep in their own soil. The flare can be buried three or four inches down in the pot. Before you dig the hole, scrape soil off the top of the root ball until you find the first structural root, and measure the ball from there.

“In many cases, trees and shrubs are sold with their roots and trunk already covered with too much soil.” (University of Maryland Extension, Planting a Tree or Shrub)

3. Ignoring settling

Loose soil under a root ball compacts as it is watered, and the tree sinks. Set the ball on firm, undisturbed soil at the bottom of the hole, or dig the hole an inch or two shallower than the ball is tall. High is recoverable; low is not.

4. Mulch volcanoes and soil against the trunk

Mulch piled against bark keeps it wet, invites rot and rodents, and encourages roots to grow up into the mulch and around the trunk. Spread mulch wide and flat, two to three inches deep, and pull it back so the flare and the first inch of trunk are in open air.

“Keep mulch about 3 inches away from the base of tree trunks. Mulch should never touch the trunk of the tree.” (University of Maryland Extension, Mulching Trees and Shrubs)

5. Leaving the packaging on

Stakes, ties, trunk wraps, tags, wire baskets and burlap are all temporary, and the basket and burlap come off entirely before the ball goes into the hole, not just the top third. Set the ball at the edge of the hole, cut the twine, cut the wire basket apart and lift it off, then peel off all of the burlap before the ball goes in.

Much of it is synthetic and never rots. Even natural burlap takes years to rot, and treated burlap is made to resist rotting. Until it is gone it holds the roots in the shape of the ball, so the tree stays root-bound in its own wrapping. It then grows the circling and girdling roots of mistake 6. Maryland Extension’s instruction for a basket is to cut it off and remove it. Ties left on for a second season cut into the trunk and can girdle it; remove ties and stakes within a year.

“Synthetic burlap will not decompose in the soil and can cause roots to girdle the tree.” (Clemson Cooperative Extension, Planting Trees Correctly)

6. Leaving circling roots uncorrected

A container tree with roots wrapped around the pot will keep growing in that circle and eventually strangle itself. Shave an inch off the outside of the root ball on all sides and the bottom, or cut it in a box shape. It feels brutal. The tree will thank you.

“Inspect tree root ball for circling roots and straighten, cut, or remove them.” (International Society of Arboriculture, Planting a Tree)

7. Weed fabric

Landscape fabric under mulch stops water and air, lets weeds root in the mulch on top of it anyway, and turns into a shredded plastic mess within a few years. Skip it. Mulch alone does the job if you keep it topped up.

8. Sprinklers on the trunk

A lawn sprinkler that wets the trunk every morning keeps the bark saturated and grows fungus and rot on the lower stem. Water the root zone, at the soil, and keep spray heads aimed away from trunks.

9. A small, deep hole with amended backfill

Roots grow outward, not down. Dig wide and shallow, two or three times the width of the ball and no deeper. Backfill with the soil you dug out, not bagged compost or topsoil; a pocket of rich soil in heavy clay collects water like a bathtub and roots refuse to leave it.

10. Planting at the wrong time and then forgetting to water

The right time to plant is the dormant season, and the best moment in it comes early: soon after the tree has dropped its leaves in fall, while the soil is still warm. A tree planted then has the whole dormant season to grow new roots before it has to carry leaves, and it meets its first summer already anchored. Early spring, before bud break, is the second choice. Summer, with the tree in full leaf, is the mistake for a bare-root or balled tree, and so is planting into frozen or waterlogged ground in any season.

Extension services make an exception for a few fleshy-rooted species, dogwood, magnolia and yellowwood among them, and for broadleaf evergreens, which they plant in early spring instead. In the North, bare-root trees and oaks are safer planted in early spring.

Whenever you plant, the first year of watering decides whether it establishes. The watering calculator turns trunk size, weeks since planting and the week’s rain into gallons and a schedule.

“container grown plants can be safely planted at any time of the year, but they are best planted in the fall to take advantage of the dormant season root growth.” (Clemson Cooperative Extension, Planting Trees Correctly)

What planting it right looks like

The ten mistakes above have a positive form, and this is the order we plant in at Blue Whale Trees.

1. Find the flare. Scrape soil off the top of the root ball until the first structural root shows, and measure the ball from there rather than from the rim of the pot.
2. Dig wide and shallow. Two or three times the width of the ball, and no deeper than the ball is tall measured from the flare.
3. Shave the circling roots. Take an inch off the outside of a container ball all round and off the bottom, or cut it square.
4. Set it on undisturbed soil. The ball sits on the firm bottom of the hole, with the flare at or slightly above the finished grade.
5. Take all the packaging off. Before the ball goes into the hole, cut the twine, cut the wire basket apart and lift it off, and remove every piece of burlap. Nothing stays in the hole but roots and soil.
6. Backfill and water it in. Use the soil you dug out, not bagged compost, and water as you fill so the soil settles around the roots.
7. Mulch wide and flat. Two to three inches deep, spread well past the ball and pulled back so the flare and the first inch of trunk stay in open air.

The pattern

Nearly every item on this list is a version of the same thing: treating the tree as a decorative object rather than a living system. The tree has roots that need air, water, room and an exposed flare. Get those right on planting day and most other problems never appear. The other half of the job is choosing a species that fits the spot in the first place. The tree finder narrows our catalog by zone, sun and soil. A bronze flush on the new leaves the following spring is not one of the problems to worry about. A tree you are moving rather than buying follows the same rules with a tighter water schedule.

Common questions

How deep should I plant a tree?

With the root flare, where the trunk widens into the first roots, at or slightly above the finished grade. If you cannot see the flare on the planted tree, it is too deep.

Do I need to remove the wire basket and burlap?

Yes, all of it, before the ball goes into the hole: cut the twine, cut the basket apart and lift it out, then peel off every piece of burlap. Much of it is synthetic and never rots, and until it is gone it holds the roots in the shape of the ball.

Can I plant a tree in summer?

A container-grown tree can go in at any time of year, though fall is best. Plant a bare-root or balled tree soon after leaf drop in fall while the soil is still warm, or in early spring before bud break, and never into frozen or waterlogged ground.

What happens if you plant a tree too deep?

The buried flare stays wet, so the bark softens and rots, and roots that grow into the soil against the trunk thicken until they girdle it. The crown thins years later, long after anyone connects it to planting day.