Q: My Autumn Glory red maples are declining. Large limbs are dying in several of my 15-year-old trees. I understand others are seeing the same red maple issues. As they decline, I am replacing them with native black gum (Nyssa sylvatica ‘Wildfire’) that I got from Trees Atlanta. But why are the maples declining? — Mike Twilling, Cartersville
A: In cases like this, I turn to experts like Art Morris, board-certified master arborist and my go-to guy. He says the maples are likely afflicted with a condition commonly called “red maple decline.” Red maples are not bulletproof in suburban landscapes. They are affected by poor soil conditions, drought, girdling roots, improper planting depth, and pests like scale insects and aphids. They exhibit dieback of the central lead due to a combination of these factors. The decline is not related to any one specific pathogen.
Due to the way maple trees branch, it is common for them to exhibit symptoms of stress in the central leader before the symptoms show up throughout the canopy. Management of declining trees should include inspection of the root flare to be sure the trees were planted at the correct depth, regular irrigation, good soil care (including proper mulching and fertilization based on a soil test) and monitoring for insect pests.
Q: This is the second season my Ruby Falls redbud tree has been in my yard, and it seems to be doing fine. I noticed it had several new green (not purple) offshoots coming up this spring after it had blossomed. Should I prune them off or will they eventually start to “weep” like the main tree? — Alicia Gatto, Cobb County
A: Ruby Falls redbud resulted from a cross between Cercis canadensis “Covey,” which is a weeping redbud variety, and “Forest Pansy,” which has purple foliage. It is such a great looking plant that the breeders knew there would be big demand. The fastest way to reproduce a large number of identical woody plants is to graft a twig from the mother plant onto a rooted twig of a less desirable plant. That’s how your tree was produced. A healthy twig of Ruby Falls was grafted to a generic green-leafed redbud.
Now the green redbud below the graft is sprouting and the new limbs have decided to head for the sky. If allowed to grow, these sprouts will shade out your pretty tree. They must be removed at once. Duck under the limbs of your Ruby Falls, find where the green-leafed sprouts originate, and cut them as close to the trunk as you can. Do the same with any that come in future years.
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