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
1 rating

Thursday - January 17, 2008

From: Austin, TX
Region: Southwest
Topic: Invasive Plants
Title: Viability of Ehretia anacua tree for Austin, TX
Answered by: Barbara Medford

QUESTION:

I live in Austin, TX and I see you've recommended the Ehretia anacua tree for someone living here. Also, my arborist mentioned it as a replacement for non-native, invasive trees. However, the database says that it might freeze back in Austin. How tall can this tree get in Austin and if it freezes will that kill the tree? It was also listed at the nursery as "fast" grower. What's the meaning of fast growth with respect to tree growth per year?

ANSWER:

We found (we think) the previous question to which you referred, in which several replacements were listed for non-native, possibly invasive trees in Austin. One of these was the Ehretia anacua (knockaway). We agree that the mention of freeze was a little vague as to whether they were talking about freezing in Travis County or farther north, to Dallas. It is mainly native to South Texas, but according to this Texas A&M Education site, it can be found as far north as Austin. The USDA map shows it distributed all over Texas, with the county distribution map showing it in Travis County and some other counties north of that. Other information we found said that as far north as Dallas, it could freeze, but that it was freeze-deciduous, which meant it would be nearly evergreen farther south, and probably would survive freezing anyway. And another cool thing: It is considered deer resistant, a big selling point in the Austin area. Not deer proof, there is no such thing, but resistant is good.

And in reference to your question about the meaning of fast growth with respect to tree growth, we found this quote from the Manual of Woody Landscape Plants by Michael Dirr:

"Rate of growth refers to the vertical increase in growth unless specified differently. Rate, as is true for size, is influenced by numerous variables such as soil, drainage, water, fertility, light, exposure, ad infinitum.

"The designation slow means the plant grows 12" or less per year; medium refers to 13 to 24" of growth; and fast to 25" or greater."

Our database shows the estimated mature size as being between 36' and 72'.

 


Ehretia anacua

 

 

 

More Invasive Plants Questions

Eradiacation of johnsongrass along roadways
August 19, 2008 - What does latest research show on eradication of Johnsongrass along roadways?
view the full question and answer

Non-native mimosa failing to bloom in Leitchfield KY
October 29, 2011 - I have a medium size mimosa tree here in KY that usually blooms beautifully; it did not bloom at all this year. It leafed out well, needs a few dead limbs pruned, but seems otherwise healthy. Please t...
view the full question and answer

Landscaping large area in Webster KY
February 10, 2012 - We just bought a house that we fell in love with. The land around it . . . well it has GREAT potential but is seriously lacking at the moment. Trying to get the farm up and running leaves very litt...
view the full question and answer

When should I plant bermuda grass seeds?
February 10, 2010 - When should I plant bermuda grass seeds?
view the full question and answer

Absence of grass around a willow tree in Georgia
December 22, 2008 - In the past three years my Willow tree has grown from a stick to a lovely tree. Unfortunately, the grass under and around the tree is gone. Nothing left but dirt. Is there a remedy?
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