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

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
4 ratings

Sunday - April 18, 2010

From: Driftwood, TX
Region: Southwest
Topic: Trees
Title: Difference between live oaks and post oaks in Driftwood TX
Answered by: Barbara Medford

QUESTION:

What are the differences between Live Oaks and Post Oaks, and are both susceptible to Oak Wilt? Also, should we remove the Ball Moss on the branches of these trees? Or is the light green lichen on the branches more destructive?

ANSWER:

From our Native Plant Database, Quercus stellata (post oak):  "Its roots are extremely sensitive to disturbance. Susceptible to oak wilt. Not often used in landscape situations. Slow-growing and long-lived." While it is the most common oak in Texas, it almost has to be already growing on your property in order to have it. It is rarely available in nurseries because of the difficulty in transplanting it. All oaks have a long taproot which, if broken, usually results in the death of the tree within a few months, but the Post Oak is the poster child for that difficulty. More information and pictures of leaves, bark and acorns from Virginia Tech.

There are a number of the genus Quercus referred to as "live oaks," but Quercus fusiformis (plateau oak), native to Hays County, is the common live oak used in landscaping and found in the wild in central Texas. It is susceptible to live oak wilt and live oak decline when stressed by drought, so care must be taken to protect it from injury both above ground and below ground to prevent infection. Pictures from the Image Archive of Central Texas Plants.

In terms of susceptibility to Oak Wilt, this website from The Texas Oak Wilt Information Partnership How to Identify and Manage Oak Wilt in Texas classifies red oaks as most at risk and white oaks (which includes Post Oaks) as less risk. From this same website, Oak Wilt Spread, explains why the way live oaks grow, often forming "mottes" of clusters with intertwined roots, causes the live oak to be at so much risk. 

Probably the most readily noticeable difference between the two trees is that the Post Oak is deciduous, dropping its leaves in the Fall, and spending the rest of the winter with bare limbs. The Live Oak, however, is tardily deciduous, which means that it holds on to the bulk of its green leaves until mid-Spring, usually the middle of March, dumps the leaves all at once and within a week or so has fresh green leaflets appearing. 

Tillandsia recurvata (small ballmoss) is an epiphyte, which means it is an airplant, receiving nothing from the tree but living space. It is not parasitic; the fact that clumps of it are often seen on interior limbs of trees is due to those interior limbs usually being the oldest, and declining from lack of sun caused by the other branches in the same tree; ball moss is fine with shade. Pictures and more information from the Image Archive of Central Texas Plants. From Floridata, ways to spread it but not to stop it. We have known of it being used to make decorations, including Christmas wreaths, and when it falls to the ground, it nourishes the soil with nitrogen. If you just don't like it, and want it down, high winds will sometimes blow it off, long-handled pruners can knock it off, and dead limbs. when trimmed wlll often bring some with them. Then all you have to do is clean up the mess.

Lichens are an even more complex subject; they are usually composed of at least two different organisms and can also function as epiphytes on tree branches. They don't appear in our Native Plant Database because our expertise is in vascular plants native to North America. However, we found an excellent  website The Special Biology of Lichens, that will probably tell you more than you ever wanted to know.

Conclusion on comparisons of harm done by ball moss and lichens? No contest, there isn't any harm done  by either. 

 

From the Image Gallery


Post oak
Quercus stellata

Post oak
Quercus stellata

Post oak
Quercus stellata

Post oak
Quercus stellata

Escarpment live oak
Quercus fusiformis

Escarpment live oak
Quercus fusiformis

Escarpment live oak
Quercus fusiformis

Escarpment live oak
Quercus fusiformis

Small ball moss
Tillandsia recurvata

Small ball moss
Tillandsia recurvata

Small ball moss
Tillandsia recurvata

Small ball moss
Tillandsia recurvata

More Trees Questions

Fall Planting Colorado Blue Spruce in Indiana.
October 15, 2009 - I live in Northern Indiana, and I want to plant a couple of Colorado Blue Spruces that are 3-6 feet in height and Balled and Burlapped. Is it okay to plant them this time of year?
view the full question and answer

Need a drought resistant, maintenance free tree in Thomasville, GA.
April 20, 2012 - I have been through many tree forums and asked several nurseries about a good tree to plant but nobody has provided an adequate answer and I hope you can help. I live in SW Georgia (Zone 8) and need ...
view the full question and answer

Transplanting redbud from field in Edmond, OK
March 30, 2009 - I want to transplant a small redbud from a field to my yard. The trunk diam is about 1.5" and the tree is about 4' tall. What is the best way to do this? Should I plant it in a pot first?
view the full question and answer

Trees for creek side in Illinois
July 04, 2008 - I have a creek that runs along my back yard, and was wondering if you could give me some suggestions on water loving trees to grow next to it. The creek gets sun all day and is located in zone 5. (so...
view the full question and answer

Erosion controlling plants for a shady Minnesota lakeside
August 11, 2015 - I live about 50 yards from a lake and there is a steep embankment. Recently someone decided to cut the trees off the embankment and now the dirt is eroding off the embankment as well as off my back ya...
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 | JOBS | SITEMAP | STAFF INTRANET
© 2016 Lady Bird Johnson Wildflower Center