En EspaŅol

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?


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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
rate this answer
Not Yet Rated

Thursday - October 23, 2008

From: Richmond, TX
Region: Southwest
Topic: Trees
Title: Knots growing on Arizona Ash in Richmond, TX
Answered by: Barbara Medford


I have three Arizona Ash trees around my house the trunks are at least 15" in diameter. One of the three has at least 25 large knots growing on its trunk, some maybe 6-8" in size. What are they? Are they harmful to the tree? Thanks for your time and trouble.


There are several things that can go wrong with Fraxinus velutina (velvet ash), including Texas root rot, nematodes, chlorosis, cankering, mildew, fungal infections and emerald ash borer. However, it sounds more like what your tree has is galls, which is ususually non-threatening to the tree, and involves a structure to protect larvae of some insect, most often wasps. When the galls show up, it's really too late to do anything about them, and they usually involve just one generation per year. See this article from the Kemper Center for Home Gardening Galls on Trees. It has suggestions for Integrated Pest Management, but just about all the information we could find on galls said it was nothing to really worry about. Most of the pictures we could find of galls were on oak trees, but they tend to be tree-specific, so something that likes to live on an ash may be causing the bumps on your tree. Look at these pictures of galls on trees to see if there are similarities to what your  trees are experiencing. 

Since we are not entomologists and, of course, cannot see your trees, we would suggest you contact the Texas A&M AgriLIFE Extension office for Fort Bend County.  This site has contact information and also an Horticulture link. They may recognize the symptoms and know what it is and whether you need to take any action about it. 


More Trees Questions

Young oak damaged by falling tree from San Diego TX
June 27, 2012 - My neighbor's Palo Blanco tree was struck by lightning and fell over our fence and on to a young oak tree in our yard. We waited a few days to see if the neighbor would offer help, but he never did,...
view the full question and answer

Magnolia species are allelopathic
August 02, 2014 - Have a healthy Southern Magnolia tree around 8 years old. It seems like everything I plant next to it dies.: Variegated Spirea, Stokes Aster, Hydrangeas. Is there something it secretes like the waln...
view the full question and answer

Native Desert Willow and bunchgrass for Lubbock TX
July 29, 2013 - We live in Lubbock and have decided to try to make our front yard as native as possible. It has been a very difficult process finding native species locally (even the local Aggie nursery sells a lot ...
view the full question and answer

Supplier for non-native Norfolk Pine to East Texas
March 17, 2013 - I would like to buy a Norfolk Pine Tree for my uncle who lives 90 miles east of Dallas, Texas. He saw my Norfolk Pine tree in CA which is 30 to 40 ft. tall. Where can I find a company that will ship...
view the full question and answer

Spots on persimmon tree leaves from Dripping Springs TX
July 10, 2013 - We are in rural Hays County Texas off Hamilton Pool Rd Texas. Large persimmon trees are turning yellow, blackish spots on underside of leaves. What do we do?
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
© 2015 Lady Bird Johnson Wildflower Center