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 Diseases and Disorders Questions

Brown rings on grass under live oaks in Austin
June 13, 2013 - There are brown rings in the grass at the dripline on several Live Oak trees in our neighborhood. What causes this? The trees appear healthy.
view the full question and answer

Transplant shock in Vacccinum corymbosum (highbush blueberry)
June 28, 2007 - Blueberry plants - We planted Northland and Blue Crop, 2 of each. All 4 plants have some leaves that are turning brown. This starts at the tip of the leaf, eventually encompasses the entire leaf, a...
view the full question and answer

Identification of gooseberry plant
July 12, 2007 - Grew up in Colorado, our yard and several near us had medium to large size deciduous shrubs that produced small (.25"-.375") red berries that were very tomato-like. Delicate with a thin skin, sligh...
view the full question and answer

Mountain Laurels are dying in Georgetown, TX.
April 02, 2012 - Ten year old Mountain Laurels both last year and this spring have had entire branches turn brown just after blooming this Feb. Round Rock Arborist suggested I contact you. Last year one of my laurels...
view the full question and answer

Freeze damage to non-native Philodendron selloeum in Deltona FL
June 22, 2010 - My philodendrons selloeum died this past winter in the freeze,came back slowly this spring and now are suffering with very small deformed leaves. Some do grow but are getting large brown dry areas on ...
view the full question and answer

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