Contact Us Host an Event 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
6 ratings

Wednesday - May 12, 2010

From: Austin, TX
Region: Southwest
Topic: Diseases and Disorders
Title: Red-backed bugs on mountain laurel (Sophoro secundiflora)
Answered by: Nan Hampton

QUESTION:

I found red-backed bugs (in fact two end-to-end like the east Texas love bugs) on my mountain laurel which has been losing leaves. Are these bugs the culprit?

ANSWER:

Sophora secundiflora (Texas mountain-laurel), according to the US Forest Service "...are primarily pest-free, except for infestations by caterpillars of a moth in the family Pyralidae."  The moth is Uresiphita reversalis (Pyralid moth or Genista broom moth).  You would see the caterpillar and its damage from chewing on the leaves if they were infesting the plant.  Obviously the bugs aren't the caterpillars and since there don't seem to be any other serious insect pests I don't think the bugs are the culprit.  The Forest Service site does mention that the mountain laurels are especially susceptible to phenoxy herbicides.  One of the commonest of these phenoxy herbicides is 2,4-D.  These particular herbicides are used against broadleaf weeds on grass lawns, pastures or in grain fields.  The problem is that they are very volatile and can drift for miles with the wind and effect plants far from their application. They have been especially detrimental to grapevines.  If you or your neighbors have been using any of these on your lawns, it is possible that some has landed on your mountain laurel and is causing the problem. 

Another possibility is that you have had some environmental change where the plant is growing.  Mountain laurels like well-drained soil to grow in.  They don't like having 'wet feet'.  Has the drainage in its vicinity changed?  Is there the possibility that the soil has become compacted by a lot of traffic—foot or vehicle?  If you think that this has happened, you need to remedy this by stopping the traffic and adding a hardwood mulch over the soil surrounding the tree.  It will help protect the roots and eventually work its way into the soil and relieve the compaction. Better yet, you could carefully work some of the mulch into the soil so that when the tree does get water (from rain or supplemental watering) the water gets to the roots and doesn't stand on top of them.  Whatever you do, don't fertilize the tree. In the first place, native plants don't need fertilizing and a plant under stress (as yours seems to be) should never be fertilized.

 

More Diseases and Disorders Questions

Sooty mold on Texas Sage in Heath TX
December 09, 2010 - I have a Texas Sage that has developed a mildew, blight, fungus or (?) condition. Something has attacked the leaves with a black sooty condition. What is this and what can I do to help this plant thri...
view the full question and answer

Problems with non-native artichoke from El Paso, TX
May 25, 2014 - I have a five year old artichoke plant in the ground that gets sun and some shade, has plenty of fertilizer and compost. Gets enough water. It has been beautiful in years past and last year had 10 a...
view the full question and answer

Sap dripping from a lacey oaks in San Antonio
September 06, 2012 - I have a lacey oak tree, approximately 6 ft. tall that has been in the ground almost a year. The tree looks healthy but there is a small area on the trunk that looks and feels wet. The substance is s...
view the full question and answer

Failure to flourish of Trumpet Creeper in Leesburg VA
June 28, 2011 - Dear Mr. Smarty Plants: Late last year I planted a trumpet creeper vine to grow on my fence and attract hummingbirds. It gets full sun, is in average soil and gets adequate water. I put a few daylilli...
view the full question and answer

Why are my lemon Cyprees trees turning Black?
April 01, 2010 - I have 3 lemon Cypress plants - all are about 6 feet tall. One of them has started turning black on one side - like it's been burnt. The inside of the plant is also turning black. I assume something ...
view the full question and answer

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