Gardening: Leaves often tell the tale of tree’s health

Nancy Szerlag
Special to The Detroit News

Our trees have taken quite a beating over the past couple of years. A drought a couple of years ago followed by two brutally cold winters have taken their toll. In my condo complex the small landscape trees have been particularly hard hit. The condition of their leaves tells me many are not long for this world.

It won’t be long before fall is here and the trees turn to gorgeous giant bouquets of yellow, orange and red. Sadly, that fabulous color show lasts but a few weeks and then almost overnight the leaves fall away. Before this colorful extravaganza begins is a good time to inspect your trees for problems because in summer their leaves can help assess the health of the tree.

Leaves that lose their bright green color before their time indicate the tree has one or more issues. Leaves that turn yellowish-green in color are suffering from chlorosis, which can be caused by a number of stresses, including root damage, temperature extremes, herbicide misapplication, disease pathogens, water issues and more.

Other indicators are new growth that is stunted, early leaf drop and twigs and branches suffering dieback.

Don’t overlook landscape giants when inspecting trees. Stand a good distance away and look at its structure from all sides.

A thinning canopy and undersized leaves are a big red flag. But this may be happening in only a portion the tree and hidden from regular view.

Leaning can also be a signal of trouble, especially if there are exposed roots or a mound of soil near its base. Straight-line winds could topple such a tree, so have a professional assess the tree’s stability.

Large trees with multiple branches arising from the same point in the trunk may have weak attachments and separate during a storm, bringing down all or part of the tree. Inspect the trunk and large branches for cavities, cankers, mushrooms and large growths called conks. Mushrooms and conks at the base of a tree are a sign of decay.

The final step is to look down at the base of the tree. Damage from rodents, string trimmers, roots encircling the tree and/or a flat-sided trunk are also red flags. Removing strangling roots and exposing buried root flairs using an air spade may save the tree and save you big bucks removing it.

A trained arborist can evaluate the tree’s condition and its potential as a hazard.

To locate a certified arborist in you area go to the Tree Care Industry Association website:

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