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
3 ratings

Sunday - April 27, 2008

From: Leander, TX
Region: Southwest
Topic: Pests, Herbs/Forbs
Title: Problem with Eupatorium greggii
Answered by: Barbara Medford

QUESTION:

At the Garden's fall plant sale in 2006, I bought some Eupatorium greggii. It did very well last year. Recently, the entire plant looks like it is just wilting from the top down, as if it has some sort of disease. Moisture is not the problem. The Conoclinium greggii I have elsewhere does not seem to be affected. Do you have any idea if this plant is prone to a virus? Any other ideas?

ANSWER:

Eupatorium greggii is now considered a synonym for Conoclinium greggii (palmleaf thoroughwort), which explains why we couldn't find Eupatorium greggii in the Native Plant Database. Beyond that, however, we are still very puzzled as to what could be causing your plant to decline. Have you checked for red spider mites or whiteflies? Try tapping an affected leaf over a sheet of white paper-if you get little red spots, that's red spider mites. If you see what looks like flying dandruff, that is whiteflies. Honeydew excreted by whiteflies glaze both upper and lower leaf surfaces, causing the development of black sooty mold fungus. Just about every reference we checked referred to Conoclinium greggii (palmleaf thoroughwort) as almost pest and disease free, but you may have gotten caught in the "almost." The only other possibility we could think of is that this plant needs afternoon shade, and if it is in full sun all day, it will need additional water. These are very sturdy plants, and spread by rhizomes, which sometimes makes them almost a nuisance, but they are wonderful for butterflies. We would suggest that, if you feel the insects mentioned are the culprits, that you first trim out all the affected foliage, and dispose of it where the insects living on it will not be transported to other plants. Then try a weak solution of Safer insecticidal soap, sprayed on it two or three times in a week, because of the various stages of development the whitefly goes through. The main point is to prevent the spread of these insects to other plants in your garden, so you'll need to keep a watch out for that.

 

More Pests Questions

Topical treatment for poison ivy rash
November 12, 2008 - I would like to know a topical treatment for the poison ivy rash
view the full question and answer

Identification of insects on crepe myrtle in Florida
May 22, 2013 - I have large colonies of striped bugs on large crepe myrtle in my backyard. They stay in large groups and have long antennae. There are larger black bugs among the groups that appear to corral and g...
view the full question and answer

Long term effects of pesticide from Lubbock TX
March 20, 2013 - I have 9 western pecan trees about 20 years old. Trunk sizes is from 18" to 39". I used a product Bayer Tree and Shrub, applied to the trees. I wonder what it will do to the trees. I talkd to Bayer ...
view the full question and answer

Caterpillars attacking mountain laurel in Marble Falls TX
August 27, 2009 - What are the caterpillars that eat up our mountain laurel? Nothing left but a few stems.
view the full question and answer

What causes rock rose branches to snap off?
August 30, 2013 - my small texas rock rose branches keep snapping in the center. What is causing this and what can I do?
view the full question and answer

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