En EspaÑol

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 - September 28, 2008

From: Iredell, TX
Region: Southwest
Topic: Pruning, Trees
Title: Pruning native Senna lindheimeriana
Answered by: Barbara Medford

QUESTION:

I asked a question about pruning a Texas Senna tree. The Texas Senna I have is either a S. wislizenii or a S.lindheimeriana. It is a beautiful tree that I purchased at a Texas Native Plant nursery. Like I said in my previous email, it is about 7 to 8 feet tall and and about 7 feet across. It has small green leaves and is very bushy and full. My question was how and when do I prune it. Can you please give me some information on this?

ANSWER:

Oops, sorry, you're absolutely correct. Our mistake was to look for the "Texas Senna" in our Native Plant Database, and it wasn't found under that name. The "Texas Senna" we did find was a non-native. This is the problem we run into when retailers name their plants without regard to botanical names. Fortunately, you apparently got (and saved) a label with the proper botanical name.

Senna lindheimeriana (velvet leaf senna) is a tender perennial and considered a sub-tropical herbaceous plant. Senna wislizeni (Wislizenus' senna), on the other hand, is referred to as "shrubby", has thorns, and can apparently take lower temperatures. 

We did not find any pruning instructions for either plant; however, we did learn that in colder temperatures, Senna lindheimeriana (velvet leaf senna) will die back, but will come back from the roots. For that reason, we would suggest that you let it run through its blooming season (apparently October is the end), and then trim it back pretty thoroughly. When we prune a plant like that, we always leave stalks sticking up 8 to 10 inches, just so we'll know where it is. If you are expecting some pretty cold weather, it would be a good idea to mulch the roots. The plant should begin to come back from the roots in Spring, and will probably grow bigger and more lush for having been trimmed back. 

If you believe that what you have is Senna wislizeni (Wislizenus' senna), we would still recommend pretty good pruning, but maybe not down as low. And, in fact, you might want to wait until late Winter, when you don't expect any more hard freezes, to do that pruning. If you prune it too soon, and there is a hard freeze, it could damage new growth starting to emerge. 

 

From the Image Gallery


Lindheimer's senna
Senna lindheimeriana

Lindheimer's senna
Senna lindheimeriana

Canyon senna
Senna wislizeni

Canyon senna
Senna wislizeni

More Pruning Questions

Trimming of Aster ericoides in Philadelphia
March 20, 2010 - Should I cut back my Aster ericoides, ‘schneegitter’ in the spring?
view the full question and answer

Survival of native yaupon in The Woodlands, TX after hurricane
September 25, 2008 - One of my large native yaupons trees (8ft) fell away from a group during the hurricane. I have uprighted and tied it off for stability. Now the leaves are all brown and falling. Is the tree dead or...
view the full question and answer

Burning back Gulf Muhly instead of trimming from San Antonio
December 19, 2011 - A few years ago I noticed that the Center burned back its Gulf Muhly rather than cutting it back. Did that study result in any conclusions or recommendations?
view the full question and answer

Pruning of tree poppy from Livermore CA
May 29, 2013 - We have a Dendromecon rigida which has been in place for about 10 years and is doing fine. But the older growth gets dry, brown and crinkly, while the newer growth is bright and lush. I would like t...
view the full question and answer

Failure of older branches on Bauhinia lunarioides to thrive
April 27, 2008 - We planted a sapling of the Anacacho Orchid Tree (Bauhinia lunarioides) winter (Jan, Feb?) and now it has leaves and blooms - but only off of new branches near its trunk, as the old branches haven't ...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2015 Lady Bird Johnson Wildflower Center