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 Shrubs Questions

Need for smaller tree with less invasive roots from Ft. Worth TX
June 07, 2014 - The sycamore in the front yard has developed roots larger than the branches. They have decided that the water and sewer lines are perfect to acquire their water from. For this reason it will be coming...
view the full question and answer

Native perennials for Donley County, TX
July 16, 2009 - What are the best perennials to plant in Donley County, TX?
view the full question and answer

Thorny shrub to use as a barrier in Michigan
June 12, 2010 - What shrub/bush/tree would you recommend that grows fast, very thorny to act as a very strong deterrent/barrier that gets at least 4' tall? It would be in an open yet removed area from foot traffic ...
view the full question and answer

Freeze damage to dwarf Barbados Cherry in Austin
April 23, 2010 - This past winter was colder than usual here, in the southwestern outskirts of Austin, but I am surprised that my established Dwarf Barbados Cherry, on the south side of my house froze completely to th...
view the full question and answer

Evergreen native shrubs for hedge in Austin
November 20, 2008 - Please help! Looking for an inexpensive, fast growing shrub or tree to plant along 200' fence in our backyard. Lots of sun (southwest side) but I wouldn't call it dry. Hoping for something that k...
view the full question and answer

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