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
17 ratings

Sunday - September 14, 2008

From: San Antonio, TX
Region: Southwest
Topic: Diseases and Disorders, Pruning, Trees
Title: Pruning mature cedar elm trees in San Antonio
Answered by: Barbara Medford

QUESTION:

When is the right time to prune my several mature cedar elm trees? I'm in San Antonio, and they have never been trimmed in the 55 years we have lived in this home. I have several that are at least 70 ft tall and they need cleaning up. I wouldn't want to harm them, though.

ANSWER:

Ulmus crassifolia (cedar elm) is a native North American deciduous tree which reach 50 to 90 feet in height with a spread of 40 to 60 feet. It would be a low maintenance shade and street tree except for its thin drooping branches which are somewhat susceptible to breakage at the crotches of major limbs. Some of this could be avoided by maintaining a regular pruning and training program in the early years after transplanting. For more information, see this USDA Forest Service website on Cedar Elm.Your elms have already had a pretty good life span, at 55+ years, and are at a height to be expected at their age. They have a fairly long life span, perhaps 150 to 300 years. So, at first glance, we could say your elms have been doing just fine, and need no trimming, etc.

However, the main drawback to the elm is Dutch elm disease. Dutch elm disease was first discovered in Ohio in 1930. Spores of the disease are carried on the bodies of elm bark beetles and are deposited in tree wounds. The beetles, perhaps introduced accidentally from Asia, attacked trees that had not had a chance to develop a resistance to the disease over time. It is caused by a fungus transmitted by two species of bark beetles.

Avoid pruning from April to August. The elm bark beetle is attracted to freshly cut elm and is most active during this period. Prune dead or dying branches from Fall to late Winter. We would urge you to engage a licensed arborist, for several reasons. They will be aware of the potential problems for the elm tree, and know when is the appropriate time for pruning. Also, they will have the equipment and expertise for dealing with such a large tree. Please don't climb up your trees with a chain saw. You will possibly damage a whole lot more than the tree.


Ulmus crassifolia

Ulmus crassifolia

Ulmus crassifolia

Ulmus crassifolia

 

 

More Pruning Questions

Trimming of Flame acanthus from Bastrop TX
February 17, 2012 - My flame acanthus never lost leaves off the bottom tier of branches this winter. With the brief warm weather and rain we've had, the top and middle tier of branches have all re-leafed. It is very l...
view the full question and answer

Failure to bloom of Tecoma stans in Austin
August 02, 2008 - We Planted a Yellow Esperanza shrub 2 years ago that was blooming when we purchased it. It bloomed very little last year and not at all this year. It looks very healthy and each year gets about 10 f...
view the full question and answer

Pruning buttonbush from Pottsville PA
December 10, 2013 - In a formally planted park, a small area has become swampy. I have choosen to plant it with wet tolerant native plants. I would appreciate any suggestions on pruning the buttonbush [Cephalanthus occ...
view the full question and answer

Questions about care and pruning of Mexican Plum and Mountain Laurel in Austin, TX.
January 24, 2012 - I have a couple of questions regarding tree care and pruning. I have a Mexican Plum (Prunus mexicana), about 10 years old or so. I would like to prune it. Is it ok to prune now in late wi...
view the full question and answer

Non-branching mimosa tree
June 26, 2008 - I have a Mimosa Tree, just about 2 years old, grown from seed. The problem with it is that it has not branched out, it looks like one long branch growing out of the ground, about 5 feet if stood strai...
view the full question and answer

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