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
1 rating

Saturday - April 19, 2008

From: Austin, TX
Region: Southwest
Topic: Trees
Title: Problems with sophora secundiflora
Answered by: Barbara Medford

QUESTION:

My mountain laurel is looking bad. It has lost of its leaves, especially on the lower part of the tree (it's about 7 feet tall) and many of the remaining ones don't look good - they are curled up and spotted. The spots could be from insect eggs. This is the second year this has happened. It continues to get healthy new growth, however, and it bloomed some this year. I planted it about 20 years ago. It gets full sun. Several other mountain laurels close to it are perfectly healthy. Is this some kind of insect infestation? What should I do to care for it?

ANSWER:

The first possibility is that the leaves are chlorotic; that is, they don't have enough chlorophyll, which can cause black spotting between veins in the leaves. Plants can become chlorotic because the soil in which they are growing is so alkaline that the plant has difficulty extracting the iron that it needs from the soil. In the Austin area, particularly with other mountain laurels growing nearby, it seems unlikely that too much alkalinity is the problem. However, chlorosis in the Sophora secundiflora can also be caused by overwatering or watering too shallowly. This particular plant requires very good drainage and is accustomed to growing on limestone shelves or in very rocky soil. If your affected mountain laurel is in a low spot, a spot that accumulates moisture from runoff, or is watered by a sprinkler system, but not thoroughly, that could be causing the symptoms you are observing. Check the drainage on that tree; they need only be watered (if there has been no rain) every two to four weeks, but need to be deeply and thoroughly watered then. We think this is probably the most likely culprit.

We found several references to the genista caterpillar, apparently the larval stage of the Genista moth. Read this article on the Sophora Worm from the Maricopa (AZ) County cooperative Extension Home Horticulture site and see if any of the symptoms match the ones you are observing. Apparently, just picking off the caterpillars and/or destroying the webs that are spun by them controls that problem. If, upon close examination, you feel this is your problem, the website says you probably don't need to worry about it, but does give suggestions for control if the problem becomes severe.

 

 

More Trees Questions

Watering practices for live oaks in drought from New Braunfels TX
September 04, 2011 - We have conflicting info about watering live oaks. An arborist says to water now using soaker hoses or small sprinklers and a landscaper who spoke to our garden club said that after August is too late...
view the full question and answer

Removal of invasive non-native Chinese wisteria
September 10, 2007 - I am going to be removing my ubiquitous chinese wisteria very soon (the method I'm going to use is undetermined). If I decide to use Round-up on the cut-stem (which may take more than one application...
view the full question and answer

Possibility of symbiotic relationship between cedar elm and ashe juniper
November 14, 2006 - Is there a symbiotic relationship between cedar elm and ashe juniper? We have a small ashe juniper sapling and a small cedar elm sapling growing near each other (actually, we planted the juniper 2 yea...
view the full question and answer

Oak leaf fall causing ivy damage
August 28, 2007 - I read the A/Q in the Austin American-Statesman Saturday, August 25, regarding the leaves falling now from the live oaks. I am experiencing the same thing, but it is the leaves of my post oaks that a...
view the full question and answer

Dead portions on oak tree in Hutchinson KS
August 22, 2011 - I have an oak tree on the property I just moved into. One tree is healthy, the other has a dead side or almost dead. It did have some new green leaves on the dead branches but not many. What should...
view the full question and answer

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