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
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 Trees Questions

Privacy screening from Prosperity SC
May 19, 2013 - I need to know what would be a good tree to plant for blocking my neighbor's home it needs to be an evergreen and slender in the space it would take.
view the full question and answer

Tree for area around patio in East Texas
December 31, 2008 - What is the best type of tree to plant around my patio which faces the southeast
view the full question and answer

Need suggestions for plants for a privacy screen in Long Beach, NY.
August 10, 2011 - I have recently added 1500sq.ft. to my backyard. My backyard faces a busy road. I would like to place native trees and bushes along the fence for added privacy, shade and to protect my house from the...
view the full question and answer

Replanting a Desert Willow
February 07, 2016 - My desert willow was damaged badly in a winter storm and had to be taken down. Do I need to remove the old root system below grade when I plant a new desert willow?
view the full question and answer

Wildlife and bird friendly hedgerow for Chicago suburb
November 30, 2013 - Want to plant a wildlife/bird friendly hedgerow in suburban Chicago. Looking for a recommended mix of understory trees as well a shrubs and grasses. Site is part shade with average to wet soil and tr...
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