Host an Event Volunteer Join Tickets

Support the plant database you love!

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
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

Removing suckers from Escarpment oak in Austin
October 11, 2010 - I have a small but mature grove of Escarpment Live Oak in my back yard. Five years ago we removed the St. Augustine grass that grew under these oaks and since then root suckers have begun to grow aro...
view the full question and answer

Non-toxic trees for cattle, horses and swine in Washington state.
December 04, 2015 - What non-toxic trees can be planted in cattle pastures in Central Washington? We also have horses and swine on the property.
view the full question and answer

Propagation of redbuds from shoots in St. Louis MO
July 17, 2009 - I have a beautiful, healthy old redbud tree that I love. Every year, I find baby redbud trees rooted all over my yard, Since they are deep, I can't seem to dig them out so I simply cut them down to...
view the full question and answer

Dirt at tree base from Austin
November 03, 2012 - Hello, I recently bought a home in Austin with a live oak tree which is about eight years old. The previous owner did exactly what all the experts say NOT to do, which was to mound dirt right up agai...
view the full question and answer

Viability of Cupressus macrocarpa in Arvada, Colorado
October 06, 2008 - Can I plant lemon cypress in Arvada CO, zone 5, as landscaping plant? Can't find zone information.
view the full question and answer

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