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

Trees poisonous to horses from Landrum SC
April 15, 2012 - Please tell me if the following trees are poisonous to horses: hickory, beech, poplar, and redbud. Thank you very much.
view the full question and answer

Scorched leaves on Red Maple from Lufkin TX
April 30, 2012 - I have a Red Maple that we planted in Lufkin, TX about a month ago and fertilized about 2 weeks ago. We water the tree often. The leaves have become scorched looking on the outside of about 1/3 of t...
view the full question and answer

Planting a tulip poplar in Virginia Beach VA
November 10, 2009 - Hi. I would like to plant a Yellow Poplar, 'Tulip Tree' in my front yard. I will not be able to plant this tree until after November 15th. The tree will receive direct sun and will be exposed to hea...
view the full question and answer

Inflorescence of the American sycamore (Platanus occidentalis)
December 28, 2007 - What kind of flower inflorescence do sycamores have?
view the full question and answer

Selection of native trees to replace trees lost in hurricane
September 28, 2008 - Hello, I have a tree replacement list I must choose from as I live in a HOA deeded area. I lost 2 pines to the hurricane. And according to them I need to replace with 2 large trees. The pines were 15 ...
view the full question and answer

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