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

Need suggestions for a privacy screen besides Murray Cypress.
October 18, 2011 - Mr. Smarty Plants, I live in NE TX, about an hour east of Dallas on I-20. I hear interstate traffic behind my house, and have a busy street on its left side, and a school adjoining in back. I thi...
view the full question and answer

New growth on live oaks in Houston
September 27, 2011 - My 2 10yr. old live oaks are putting out new growth (branches?) although, here in Houston, TX we are having such a drought. For the last 3 months, I have conscientiously watered my entire yard via ...
view the full question and answer

Transplanting aspens and Colorado blue spruce trees
August 18, 2009 - Please help me with info on transplanting aspen and blue spruce trees in Colorado. I live at 8600ft and have tons of deer. thx
view the full question and answer

Pruning Wax Myrtle trees & bushes
February 28, 2016 - When is the best time of year to prune Wax Myrtle trees & bushes.
view the full question and answer

Erosion Solution for Lorton, VA
February 07, 2014 - We have a steep slope in our common area of our homeowners association. Trees that were planted have died. It is a large area around a pond. What should we plant that will hold the soil? The soil...
view the full question and answer

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