Native Plants

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.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Ask Mr. Smarty Plants

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

Search Smarty Plants

See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

rate this answer

Not Yet Rated

Wednesday - August 19, 2009

From: Austin, TX
Region: Southwest
Topic: Non-Natives
Title: Aphids in non-native crape myrtles in Austin
Answered by: Barbara Medford

QUESTION:

What is the least toxic way of getting rid of aphids? They are on a crapemyrtle and I do not think it will hold up to really forceful water spray. Due to the drought in Central Texas, our St. Augustine grass is dying. Is the grass dying from lack of water different from the way grass dies in the winter? Someone told me that it is different because in the winter the grass becomes dormant instead of really dying.

ANSWER:

While Lagerstroemia indica (crape myrtle) is not native to North America and therefore out of our range of expertise, aphids do not discriminate. The aphids are a nuisance, and you don't want to park a car or even stand very long under a crape myrtle infested with them, but they really don't do any damage to the tree. You're right, a hard spray of water would probably knock off more blossoms than aphids. Depending on how much it is bothering you and how big the tree is, you could try spraying it with a weak solution of Safer insecticide, or even soapy water.

Stenotaphrum secundatum (St. Augustine grass) is also non-native to North America and although widely used, is not really suitable for Austin, especially in a time of extreme heat and drought. It needs water and shade. It is fairly drought-tolerant when it has become well-established. If your watering is restricted and you get some brown areas in the lawn, they will still probably come back when (and if) we get some rain. Even if the grass in a particular area does not green up next Spring, the stolons around it will spread back into the area.