If you're planting a tree in your landscape this spring, the first rule of a green thumb is to choose the right tree for the right site. Meeting sun and shade requirements are key to the health of any tree.

Too little or too much sun puts all plants in stress, making them vulnerable to insects, disease and winterkill.

Trees such as Japanese maples or dogwoods, which naturally grow at the edge of woods, do best in areas protected from winter sun and drying winds. But tree tags don't mention those facts.

When planting trees, professionals discourage heavily amending or adding fertilizer to the backfill soil, as it discourages the roots from moving out of the planting area.

Fertilizing trees in stress can do more harm than good. The nutrients in fertilizers stimulate growth of roots, shoots, blooms and/or fruit. In spite of what you see on TV, fertilizers are not a source of food. All plants, including trees and grass, make their own food. Encouraging new growth from trees that have prematurely lost leaves or are slow to leaf out drains away precious reserves.

Damage caused by lawn mowers and weed whackers are a major cause of tree loss in urban settings. A mulch bed containing 3 inches of organic material surrounding the base of a tree is an easy and effective method of protection. Just be sure to keep the mulch 4 inches away from the trunk. Packing it up against the bark promotes moisture-loving diseases and rodent damage.

Mulch depth can be deceiving and layering on too much causes problems. Think of the short end of a 3-by-5 card. So, after the material has been allowed to settle, using a 1/4 inch dowel or a ruler, plunge it into the mulch layer until it reaches the soil level. Then mark the depth and measure it. If it exceeds 3 inches, remove the excess.

Grass growing under the drip line not only competes with the tree for water, the use of broad leaf herbicides on turf that close to young trees can be damaging.

Proper pruning techniques also keep trees healthy. Protruding branch stubs may cause rot, yet flush cuts, those that remove the branch collar, heal slowly, inviting invasion of bacterial and fungal diseases. However, sealing the wounds with paint or other products has also proven to be detrimental. It, too, seals in decay, causing moisture and delays healing. Mother Nature knows best, so let her do her thing.

Nancy Szerlag is a master gardener and a Metro Detroit freelance writer. Her column appears Fridays in Homestyle. To ask her a question go to and click on Ask Nancy. You can also read her previous columns at

Read or Share this story: