Host an Event Volunteer Join Tickets

Support the plant database you love!

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
2 ratings

Wednesday - September 26, 2007

From: Buda, TX
Region: Southwest
Topic: Pests, Trees
Title: Danger of lichens damaging trees
Answered by: Barbara Medford

QUESTION:

My mom lives east of Buda, Texas where she has planted many different kinds of trees, which are all over 10 years old. Now, they all have a moss or lichen growing on the bark of the trees. She is worried that this moss or lichen will eventually harm or kill the tree. So, she would like to know if there is something to use to stop this growth on the trees.

ANSWER:

Check out this excellent link from the Royal Horticultural Society on lichens and moss on the bark of trees. Briefly, it points out that lichens and moss are non-parasitic and will not injure the plants on which they grow; however, they may be an indication of trees that have been neglected. They can be controlled to a certain extent by improving air circulation by pruning out overcrowded branches.

No doubt all the (unusual) rain we have had in Texas this year has at least contributed to this sudden upswing in the lichen population. However, as pointed out above, good plant vigor is the best defense against lichens. There are no pesticides recommended for control of lichens, and it is not recommended that they be considered, as they will more likely damage the desirable vegetation than otherwise.

Incidentally, we found another very interesting website called "General Information About Lichens and Pollution." This has more information on lichens, but adds that it has been noted by scientists that the presence of lichens may indicate that the air quality in the area is good. It's not that the lichens have anything to do with making the air cleaner, it's just that they don't thrive where the air is very polluted. So, if it's any comfort, the trees you are concerned about may be telling you that the air quality around your area is acceptable, at least to lichens.

 

More Pests Questions

Black bugs on yucca from Aledo TX
April 14, 2013 - We have flowering yuccas that have thousands of small black bugs that seem to be hurting the plant. They are not on any other foliage in our beds. What do I use to get rid of them??
view the full question and answer

Tiny beetles eating a native plant in Austin, TX.
April 15, 2014 - Help! Found plant devoured in my wildflower garden! Covered with literally thousand of small black bronze beetles. They are on other plants but the other plants (native poppies, coneflower, coreops...
view the full question and answer

Turk's Cap and Pavonia insect problems
June 27, 2015 - My Turk's cap and Pavonia lasiopetala (rock rose) plants both have quite a few leaves that are skeletonized in appearance. I do not see any insects on the underside of the leaves. What could be cau...
view the full question and answer

Topical treatment for poison ivy rash
November 12, 2008 - I would like to know a topical treatment for the poison ivy rash
view the full question and answer

Help for Collapsing Tradescantia
August 14, 2013 - My tradescantia has completely collapsed at the crown. The stems are yellowish. This happened once before when I had it planted in full sun and I just had to discard it. This time I have one plante...
view the full question and answer

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