Rent Shop Volunteer Join

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
3 ratings

Monday - August 18, 2008

From: Kaufman, TX
Region: Southwest
Topic: Trees
Title: Avoiding cedar elm because of allergens
Answered by: Barbara Medford

QUESTION:

Hi. Cedar elm, Ulmus crassifolia, seems like a wonderful, tough, drought tolerant native tree. I'd like to plant several to shade buildings. I'm being discouraged from doing so because Cedar elm pollen is allergenic. I've been researching and having a hard time finding out how far the pollen travels and how bad it really is. There's plenty of Cedar elm growing on nearby properties, so isn't the pollen going to be blowing around anyway, whether we plant more of the tree or not? Or does it make a significant difference for allergic people if they walk under a tree? Thanks.

ANSWER:

In Texas, the calendar of allergies from tree pollens appear March through May. These are mostly pollens of ash, oak, box elder, hackberry, sycamore, walnut, elm, hickory, pecan, mesquite, and mulberry. The Fall Elm, or Cedar Elm, pollinates in August, September and October. Grass pollen season extends from May until August. Weed pollens are predominant July through October. For most parts of the country, winter is pollen free, but in Central Texas we have "cedar" (Ashe Juniper) December through March. Conclusion: If you live in Texas and have sensitivity to allergens (which lots of people do) you are going to have problems with pollen virtually year-round. This information came from an excellent website from BNet Business Network "Trees 'n Sneeze".

It has been suggested to you, apparently, that you not plant a particular tree (Cedar elm) because of its pollens. Pollen is the result of plants needing to reproduce themselves. The pollen is a vital link in that need, and there is going to be pollen, regardless. The benefit you are seeking is shade for buildings, but this Trees Are Good website "Benefits of Trees" gives many more benefits. As you pointed out, there are lots of other Cedar elms around, and you would not be contributing a great percentage to the allergy problem. All of the trees listed on the calendar of allergies are native, which is good. We are going to list the trees we consider as good shade trees for your part of the state, and you can follow the links to our web pages which will give you more information on each tree. Considering that all are going to put pollens in the air, you can then choose a tree that is best suited for your purposes.

Fraxinus americana (white ash)

Quercus palustris (pin oak) - good in East Texas, likes sandy, acid soil

Acer negundo (boxelder) - fast growing, planted for shade, but short-lived

Celtis occidentalis (common hackberry)

Platanus occidentalis (American sycamore)

Juglans nigra (black walnut)

Ulmus crassifolia (cedar elm) - susceptible to Dutch Elm Disease

Carya texana (black hickory)

Carya illinoinensis (pecan) - slow growing, difficult to transplant because of large taproot, susceptible to a number of pests and diseases.

 

 

 

More Trees Questions

Shrubs and trees over septic tank in Killen AL
May 20, 2013 - Our church has 5year old blue rug juniper, a crape myrtle and two shrubs I can't identify planted over the septic tank which is surrounded with concrete and asphalt. I am afraid these will cause a pr...
view the full question and answer

Native landscaping plants for Sherman, Texas
December 19, 2007 - We are starting from scratch on landscaping our new yard. We live in Sherman, TX and I would like to use plants and flowers that are native to Texas and have a good chance of surviving. What are you...
view the full question and answer

Pruning Texas madrone trees from Utopia TX
August 19, 2012 - I have a number of large Texas Madrone trees on my ranch in Utopia Texas. A few of them have dead limbs and I was wondering whether I should cut off the dead limbs or just leave the tree alone. I wa...
view the full question and answer

Shade Trees for Bullhead City, AZ
August 12, 2014 - We have a patio with 2 old (unused) fire pit cut-outs; about 4 ft wide each. The cut out is not lined with concrete or brick: just rimmed with the concrete on all sides. The center of the cut-outs i...
view the full question and answer

Determination of the sex of Mexican persimmon (Diospyros texana)
January 30, 2008 - Last spring, I planted a persimmon fruit from a Mexican Persimmon. I now have 6 small seedlings coming up. Since they all came from the same seed source - 1 black persimmon, will they all be male tree...
view the full question and answer

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