En EspaŅol

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
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

Sunday - May 02, 2010

From: Austin, TX
Region: Southwest
Topic: Pruning, Watering, Trees
Title: Failure to thrive of Texas Mountain Laurel in Austin
Answered by: Barbara Medford

QUESTION:

I have an adult (over 25 years?, 20 feet tall?) Mountain Laurel next to my house in Austin. The winter of 2009/10 it lost most of its leaves. It did bloom and leaf out this Spring--not vigorous especially, not on the top. Is it completing its life span indicating I should take it down and replace it? Or, should I give it another year or two to see if it comes back? Possibly resulting from a combination of the drought and extreme 2009 winter weather. I don't see similar specimens in my neighborhood in similar condition. Thank you for your advice.

ANSWER:

Sophora secundiflora (Texas mountain-laurel) is native to the Austin area, so we can't blame the problems on it being out of its territory. You are absoutely correct that even native plants, well adapted to our uncertain climate, have suffered this past couple of years. However, everything we looked at researching this plant says that its mature height is 10 to 15 ft.,  but none of the material said how old it was expected to get. Generally speaking, the slower a plant grows, and this one grows very slowly, the longer it will live. So, it would seem your tree is mature, but not necessarily senile, ready to die. The only possible change we can think of that might cause some decline in a tree that well developed is if there has been a change in the drainage. This is a plant accustomed to growing in desert areas and limestone, which is why it is so slow-growing. It needs good watering, especially in Spring and Summer, but also good drainage. If it has not been receiving supplemental watering during the very dry last two years, and now there has been rain, it may have feet standing in water beneath the surface of the soil, especially if you have clay soil. 

We certainly would not recommend taking down a mature and apparently healthy tree just yet. Don't fertilize it.  Often, that is a knee-jerk reaction when a plant does poorly, to fertilize. A plant under stress should never be fertilized, and with this tree, with the blooming already past for this season, you sure don't want to send a message to inspire new growth. Furthermore, this is a plant that really should never be fertilized, it is so well-adapted to its environment. Make sure it is getting plenty of deep watering, but that the water is draining. If water stands on the plant 30 minutes before it disappears into the soil, you have a heavy clay soil. Try mulching the root area, reducing the amount of water put on the roots each time, but increase the frequency. We would definitely give this tree another year or so, before it was eliminated from your landscape.

From Our Native Plant Image Gallery:


Sophora secundiflora

Sophora secundiflora

Sophora secundiflora

Sophora secundiflora

 

 

More Trees Questions

Black coloration on Star Magnolia is probably sooty mold.
November 21, 2008 - I have a star magnolia where 90% of the bark has turned black. It almost looks burned. The tree has decent buds set for next spring. What is causing the bark to turn black?
view the full question and answer

Possibility of saving hurricane-damaged Umbrella Magnolia
October 12, 2005 - Our beautiful umbrella magnolia Magnoliaceae Magnolia tripetala was toppled during Hurricane Katrina. We have lifted it back in place, however it looks very distressed. I have the following questions:...
view the full question and answer

Philadelphus ernestii under live oak in Pflugerville TX
April 05, 2010 - Will Philadelphus ernestii thrive in the root zone of live oak, or would the oak inhibit its growth? I'd like to plant it just at the edge of the canopy.
view the full question and answer

Deadheading seedless desert willows for continued bloom in Phoenix AZ
May 31, 2010 - We planted two seedless desert willow trees this spring. Both have bloomed nicely but we now have many stems with the spent flowers still on the tree. Your database for this plant says to "Remove spe...
view the full question and answer

Repairing Damage to Oak Tree Bark
February 02, 2016 - I have destructive horses who have torn a lot of the bark off of my oak trees. I've moved the horses from that area, but is there something I can put on the places where the bark is missing so the tr...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2016 Lady Bird Johnson Wildflower Center