Rent Shop Volunteer Join

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

Lily plants being chewed from Austin
June 20, 2013 - Something is chewing my lily plants to the ground. Any ideas what and do I stop them?
view the full question and answer

What insect eats Alamo Fire blue bonnets from League City TX
June 10, 2013 - What insect eats Alamo Fire blue bonnets? Something seems to be eating new seedpods.
view the full question and answer

Weedy buffalo grass from Dripping Springs, TX
March 07, 2013 - I have a buffalo grass lawn. It is thin and filled with weeds. I would like to find a solution to improve my lawn. I prefer a native grass but I need to be able to control the weeds and I am not ph...
view the full question and answer

Eliminating wood roaches from hardwood mulch from San Antonio TX
February 05, 2013 - How can I eliminate the numerous wood roaches in my hardwood mulch that I get for free from the city of San Antonio?
view the full question and answer

Problems with beheaded non-native Gerbera daisies in Cooperstown, NY
May 31, 2009 - I planted my gerberas in my perennial bed - as usual. Something is beheading them and leaving the blooms along side the plant. Some of the bloom is eaten but most of it is right there. I have t...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.