Scientists believe brilliant fall colors may be a sign of healthy trees in the expanse of the North American forests. The presence of brilliant reds of the black tupelo, orange and purples of sassafrass and the luminescent yellows of birch may actually contribute to deterring leaf-eating pests and aid in storing energy and the function of dropping leaves.
Fall colors seem to have a hypnotic effect on people, causing parents to perch their babies up high in order to have a picture background of golden gingko leaves and go on forest walks under scarlet oaks that have given a confetti carpet of crimson.
The lure of color in the fall may lead gardeners to consider planting trees this fall. When choosing trees for fall color it is best to buy and plant them in the fall, ensuring the gardener gets the most brilliant hue. Most horticulturists encourage fall tree planting because the tree does not go through the stress of Illinois summers while rooting out.
As long as the ground is diggable, trees can be planted in the landscape. Be sure to dig holes wide and shallow like a bowl and make sure to plant the top of the roots right at soil level. Surveys done by the International Society of Arboriculture indicate about 75 percent of trees planted are too deep. In a recent tree walk with Livingston Master Gardener trainees at a local park, all 4 of the trees planted that spring were planted too deep. They did not have a trunk flare and we had to dig down at least 2 to 4 inches to find the first roots. Sandy Mason, horticulture educator from Champaign County, suggested digging them back up and planting them at the correct level to keep them from being a problem.
During the first three years of a transplanted tree's life, love must be given in the form of additional water. The rule of thumb for trees is about an inch a week if it does not rain.
Mulch rings are almost as important in the success of a tree as planting at the correct depth. Spread 2 to 4 inches of mulch the width of the branch canopy, taking care not to allow mulch to be in contact with bark.
Do not prune in fall but wait until spring. Leave small branches on trunk until they reach an inch thick. Pruning is the most effective in the first 10 years of a tree's life.
Trees to plant for fall color are black tupelo, scarlet oak, hophorn beam, sourwood, birch, ginkgo, katsura tree, poplar, service berry and sassafrass. Shrubs to plant for fall color are oakleaf hydrangea, smokebush, witchhazel and highbush blueberry.