En Español

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?

Share

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

Friday - October 02, 2009

From: Georgetown, TX
Region: Southwest
Topic: Pests, Shrubs
Title: Purple sage with black residue on leaves in Georgetown TX
Answered by: Barbara Medford

QUESTION:

I have 2 very healthy tx. purple sage that have developed a black residue on some leaves, and is a "sticky" substance..any ideas what this is and how to treat???

ANSWER:

The Curse of the Common Name has struck again. You see, there are two very dissimilar plants that carry the common name "purple sage." One is Leucophyllum frutescens (Texas barometer bush), which we call cenizo and which is native to Central Texas. Four others are members of the genus salvia, a herbaceous blooming plant: Salvia dorrii (purple sage), Salvia dorrii ssp. dorrii (purple sage), Salvia dorrii ssp. dorrii var. incana (purple sage) and Salvia leucophylla (San Luis purple sage). While none of them are native to Texas, they could probably have been purchased from area nurseries.

In this case, which plant it is doesn't really matter because we think you have aphids, which are usually small and difficult to see, and the black stuff is a sooty mold which has grown on the sticky exudate of the aphids, called honeydew. This University of California Integrated Pest Management article on Aphids gives you information on control.  Neither the aphids nor the sooty mold are likely to cause real damage to the plant but are unsightly. When you read the article you will learn that a good stream of water on the plant will wash many of the offending little bugs off, and they can't get back up there after they are washed off. 

From our Native Plant Image Gallery:


Leucophyllum frutescens

Salvia dorrii

Salvia dorrii ssp. dorrii

Salvia dorrii ssp. dorrii var. incana

Salvia leucophylla

 

 

 

More Pests Questions

Need help with powdery mildew and mites in Bastrop, TX
July 26, 2011 - I tend to flower beds for the city. I have noticed a powdery mildew in 2 beds. It is on the Pavonia and Turks caps. I now notice mites. What should I do?
view the full question and answer

Tulip trees losing bark in OH
July 11, 2011 - We have two tulip trees in our yard that are losing their bark at the base of the trunk. I am careful with the mower keeping away from the tree when I mow. What could the problem be and what can I d...
view the full question and answer

Lopidea texana nymphs and adults feeding on Mountain Laurel in March
April 04, 2006 - What is the species name of the bright red bug (Miridae) nymphs and adults that are feeding on Texas Mountain Laurel leaves at this time (March 24) at the Wildflower Center?
view the full question and answer

Secretions of fluid from crepe myrtles
June 09, 2008 - On my crepe myrtle tree I have dozens of 1/2-inch-long narrow bugs that seem to secrete tiny drops of fluid. They appear on the branches of the tree. Are these harmful to the tree? Do I need to do ...
view the full question and answer

Leaves wrinkling on Tecoma stans from San Antonio TX
August 16, 2013 - My two year old esperanza (planted in the ground) froze back last winter, came back from the roots & has been doing well all summer. Recently one branch has leaves that are nice & green but very wrin...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | JOBS | SITEMAP | STAFF INTRANET
© 2016 Lady Bird Johnson Wildflower Center