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

Non-native Purple Hyacinth from Sylvania OH
May 21, 2012 - I am wondering if I plant a Purple Hyacinth Bean vine seed under a tree and allow it to grow up the tree trunk, will it kill the tree?
view the full question and answer

White evening primrose from Baton Rouge LA
April 16, 2013 - My husband and I have a disagreement about Mexican Primroses. I believe I have seen patches of them which are pure white. He believes they must be faded pink ones. Do white ones occasionally grow? ...
view the full question and answer

Identification of invasive plant
March 26, 2010 - I have found an invasive plant species in Martindale, Texas that I would like to identify for family members. It is taking over their pasture and is difficult to eliminate. It has not bloomed yet but...
view the full question and answer

Dog-proof grass from The Woodlands TX
April 26, 2013 - I am looking for a hardy grass that can tolerate female dogs urine. Zoysia was suggested but I am concerned about it being invasive. Any suggestions?
view the full question and answer

Landscaping a new yard in El Paso, TX
July 01, 2010 - I am starting my back yard, we want to plant some sod grass and shade trees. We were doing some research and came across the Paulownia and the Royal Empress tree. I like them since they grow very fast...
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