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From: Austin, TX
Region: Southwest
Topic: Diseases and Disorders, Shrubs
Title: Cool, wet summer effect on evergreen sumac
Answered by: Barbara Medford
First, thank you for researching your plant problems on the Lady Bird Johnson Wildflower Center website. Now, it would appear you are correct that some sort of fungal problem is causing the wilt on your Rhus virens (evergreen sumac), after the weird summer of cool June and July with record amounts of rain, and then, suddenly, August. Think about it, though. How would you look if you had stood in mud with cold water showering on you for six weeks? As you probably established when you researched the subject, Rhus virens is a native of Texas, and its habitat is naturally dry hillsides and water needs low. All hope is not lost, though. Texas natives are tough and resilient, and somewhere in the genetic memory of your sumacs are other summers when the weather was very unusual, including lots of rain. Let's don't waste those roots, yet. Before you consider amputation, how about a Bandaid or two? The major enemies of any fungal disease are sunlight and air movement. So, begin, if you haven't already, pruning away the dead wood and opening up spaces in the plant for air circulation. Leave as many leaves as you can, though, as the plant needs those for nutrition. And don't let the plant completely dry out, either. Just because it had too much moisture for a while doesn't mean it has a reservoir stored away for dry, hot days.
Don't do anything else for now, because neither the plant nor the gardener need to be involved in excavation in the heat of August and September. If, in November, you are convinced your plants are dead, then it's not only pleasant enough to get out there and dig them up, but it's also a very good time to plant a replacement. May we suggest, for your requirements of screening between yards, Morella cerifera (wax myrtle). This Texas native will grow to about the same height as the sumac of 8 to 12 feet, and is very attractive to several species of birds and butterflies. Not only that, the leaves have a spicy fragrance that makes pruning less of a chore.
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