En EspaŅol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Purple sage with black residue on leaves in Georgetown TX

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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.

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

Plant for full sun behind waterfall
March 21, 2009 - I have a 24 inch waterfall around my pool. I need to plant something behind it. I have full sun and hot Texas weather. I will be watering everyday, so what do you think would grow well in this area?
view the full question and answer

What plants grow well in Athens, TX?
January 18, 2011 - Athens, Texas, we have very sandy soil mixed with clay, what plants grow well here?
view the full question and answer

Planting shrubs and flowers under pine trees in New York
July 15, 2008 - We just started to plant flowers and the whole back side of our yard is pine trees. I was wondering what types of flowers can be planted under them, and what kind of plants or shrubs can be planted un...
view the full question and answer

Bees on non-native holly from Oakland TN
April 18, 2013 - I have bees all over my Nellie Stevens holly. Can I spray anything to alleviate this issue?
view the full question and answer

Blooming challenges with oakleaf hydrangea and bittersweet vine in KY
October 03, 2010 - 1. I cut back my oak leaf hydrangea last fall and it did not bloom this past year. Problem? 2. I have 3 yr old male/female bittersweet plants growing heartily, but no berries. Problem? Thank you!
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center