Whether you are adding new ornamentals, or simply moving existing specimens, planting them after the heat stress of summer will increase the likelihood of successful transplanting.
Trees and shrubs also undergo internal changes that promote root growth and increase tolerance to winter weather. Leaf growth during the summer produced sugars that were moved into the roots, so ample energy is available to re-establish strong root systems continue to grow at soil temperatures above 40 degrees, planting in October and early November usually will give them six to seven weeks before soils reach this temperature. Evergreen species retain their leaves during the fall and winter, so it is best to plant them in early spring, or perhaps early fall so root systems will have adequate time to become re-established before plant water demand increases.
Several ornamentals successfully can be planted in early to late fall. They include coffee tree, crabapple, elm (disease-resistant varieties only) ginkgo, honey locust, linden, sugar maple, pagoda tree and serviceberry. It is best to wait until after leaf drop later in the fall to plant birch, flowering dogwood, oak, red maple, sweetgum and tulip poplar.
Inadequate moisture during dry periods is the primary threat to transplant survival. Be sure to thoroughly soak the ground after transplanting. Frequently check newly-planted specimens to be sure the soil has not dried out. It is better to thoroughly soak once or twice a week than to water it a little every day. Providing sufficient moisture helps transplants survive adverse environmental conditions during the winter.
Two common mistakes
Two common mistakes are choosing ornamentals that grow too large for the location and improperly planting them.
A specimen planted with great expectations can grow into a headache when you have to severely prune to keep it away from the house, or the utility company must drastically cut it back to keep branches out of power lines. Be sure to dig a transplant hole that is wide enough. It should be at least two to three times the diameter of the root ball, even wider is better. A hole that is saucer-shaped is better than a bowl-shaped one.
Ornamentals should not be planted any deeper than they grew in a container or field. Use the soil line on the trunk to gauge how deeply to plant balled-and-burlapped ornamentals. A distinctive color difference on the trunk bark indicates how deeply a specimen was planted in the field.
If you are not sure how deeply to plant an ornamental, plant it on the shallow side. It is less damaging to plant a tree too shallow than to plant it too deeply.
After transplanting, apply a two-to three-inch layer of mulch. Avoid piling mulch around the base of the trunk because this may encourage rotting. A layer of mulch will help conserve soil moisture and discourage weed growth. Mulching also helps moderate soil temperatures that may cause the root system to heave out of the ground during winter freezing and thawing cycles.
Do not fertilize newly planted trees and shrubs during the first year because it will cause excessive vegetative growth at the expense of root development.
Also, amending the soil with sand, compost or peat moss is unnecessary and can keep an extensive root system from developing.
Jerry Little, is county extension agent for agriculture/natural resources.