Q. We have several firebushes whose leaves never turn that spectacular red in the fall. They just remain green until they fall off. We have fed them spring and fall, and yet there are several other firebushes, treated the same, whose leaves do change color. Any suggestions? J.L., Terre Haute, Indiana

A. Fall color or lack thereof is affected by a number of factors, including genetics of the plant and environmental conditions such as temperature, soil moisture and sunlight. While nutrition certainly also contributes, it sounds like you have some plants that lack the genetic disposition for good fall color. This is not likely to improve over time.

Firebush, or burning bush, is considered an invasive plant in Indiana, so you might consider replacing these with one or more of the following alternative shrubs with attractive fall color. Look for cultivars that are noted for good fall color at your garden center. You can take a "tour" of these plants and more at the Purdue Arboretum Explorer website, http://mlp.arboretum.purdue.edu/.

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