Editor’s note: Get Growing, written by the La Plata County Extension Office’s Master Gardener Program, appears every other week during the growing season. It features timely tips and suggestions for your garden and landscape.
By Dave Harris
Planting trees and shrubs successfully can be challenging and often involves expensive plant stock. It’s important to plant correctly the first time to enhance your chances of success.
Here are the key steps to planting a container or balled-and-burlap tree or shrub:
Depth of hole. Measure the height of your root ball. The top of the root ball should be above grade once placed in the hole (about 1 inch for a 1-inch caliper tree and 2 inches for a 2- to 4-inch caliper tree). If it’s a container tree, you will need to shave 1 inch off the sides and bottom of the root ball using a hacksaw or shovel. Your hole will be 1 inch shallower because your root ball is an inch shorter.
It’s important not to disturb the soil in the bottom of the hole. That soil needs to stay in its native form, so the tree doesn’t settle once in the hole.
Diameter of hole. Ideally, dig a saucer-shaped hole two times wider than the diameter of the root ball. The maximum depth of the hole will be right under the root ball. Digging this wide, shallow hole is the most important step in tree planting because the majority of roots will grow laterally in the top 12 inches of soil. Digging such a wide hole encourages lateral root development.
Setting the tree, removing packaging. Once the tree is properly positioned in the hole, remove the container from the root ball. With a balled-and-burlap tree, remove at least two-thirds of the burlap and wire basket.
Backfilling the hole. It’s fine to put the native soil in the hole with no amendments. If you wish to amend the backfill, add as much as 5 percent organic matter (compost) to the backfill. If you chose to amend, thoroughly mix the amendment into the native soil before filling the hole. Break up the native soil, so that clumps don’t exceed the size of your fist.
Shovel the backfill into the hole and water to settle the soil. Avoid compacting the soil with your feet. Do not place backfill on top of the root ball. Water the tree once backfilling is completed. If the backfill settles, add more soil. A well/berm 3 inches high just outside the perimeter of the root ball will help retain water.
Mulching. Don’t place mulch directly over the root ball. Use 3 inches of mulch over the backfill area and beyond. Never place mulch against the trunk as it may lead to bark decay.
Best of luck with your planting efforts.
Dave Harris became a Colorado master gardener in 2014. He lives in La Plata County.