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Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

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Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

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Friday - June 15, 2007

From: Round Rock, TX
Region: Southwest
Topic: Non-Natives
Title: Decline in non-native crape myrtles
Answered by: Joe Marcus

QUESTION:

I live in Round Rock and the ground is rocky about one foot beneath the surface. I have about 14 crape myrtles that have been doing very well for about 6 years now. Last year the leaves on 1 started turning red and then yellow and it didn't grow or flower no matter what I did. This year, 2 more besides the 1 have also started turning yellow. I sprayed for mold and also used fertilizer with iron but nothing helps. What could be going on with them?

ANSWER:

The focus of study and the limit of expertise of the Lady Bird Johnson Wildflower Center is limited to plants native to North America. Crape myrtles (Lagerstroemia spp.) are native to other parts of the world. However, we can give you some general advice. Crape myrtles are normally not very susceptible to disease or insect problems. High nitrogen fertilization can cause problems similar to those you describe. At any rate, it is usually not a good idea to feed declining plants. We would suspect a problem associated with nutrition or a root-related problem.
 

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