Thursday, July 1, 2010

Tree Myths

Plant deep and the roots will grow deeper. – Actually, trees and shrubs should be planted at the same depth as they were growing at their previous site. You can see the soil line at the bottom of the trunk. The only exception is that in heavy clay soils, you may want to plant slightly higher to take advantage of surface drainage. Planting a tree too deep can lead to all kinds of trouble. If the crown at the base of the trunk is covered with several inches of soil, the entire tree may die in a few years. Sometimes, these trees will hang on for years before going into a slow decline. They will often exhibit poor vigor and will develop cankers along the trunk. When they die years later, it appears as if something else did the job but, in fact, it was because of deep planting.

Lots of mulch is good. – Putting mulch around the base of a tree is good. But, like so many things in life, you can overdo it. Start with 3 to 4 inches of mulch which will settle down to about 2 or 3 inches later. Don’t pile it up against the base of the trunk. Leave a little bare soil for a few inches around the base of
the trunk. Excessive mulch piled onto the trunk will trap moisture and may cause it to rot. Also, roots of the tree may grow up into thick mulch and they will be more susceptible to rapid drying during hot, dry weather.

All newly planted trees should be staked. – Most trees should be able to stand on their own immediately after planting. If it is a windswept location or the tree is top-heavy with foliage, temporary staking may be needed. However, staking should never be left on more than one year. By then, guy wires may begin
to grow into the bark and cause a girdling reaction. If the tree won’t stand up by itself after a growing season or two, it is an indication that there are other serious problems with the site.

Tree wounds heal. – Animals have the ability to totally replace damaged cells and tissues. Trees, however, do not replace injured tissue. Rather, they just keep on growing new ones. When a tree is wounded, it may just grow over the wound but, a hundred years from now, if the tree is cut down, the wound will still be there inside the wood. Trees form a barrier or “compartmentalize” the wounded area and then grow around it. That is why a rotting spot in a tree eventually stops rotting and becomes surrounded by solid wood. If
the tree did not have this defense mechanism, once rot started, it would just spread through the entire plant and cause it to crumble to the ground quickly.

Water causes rots. – Technically, microorganisms such as fungi cause rot. Moisture is often needed to sustain these organisms but too much or too little water may also deter the onset of rot. That is why it is best to allow wounds to dry off as quickly and thoroughly as possible. Heavy, tar-like pruning compounds
trap in moisture and may actually encourage rots.