En EspaŅol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Disappearance of leaves on desert willow in Tucson AZ

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

Saturday - August 08, 2009

From: Tucson, AZ
Region: Southwest
Topic: Compost and Mulch, Pests, Transplants, Trees
Title: Disappearance of leaves on desert willow in Tucson AZ
Answered by: Barbara Medford

QUESTION:

We have a Lois Adams Desert Willow (Tucson, Az). The leaves will pump out and then a day or so later, all of the leaves are gone. The only bugs we've seen on it are very, very small ants. Could this be what is eating the leaves? We have two other desert willows in different locations; however, they are doing great.

ANSWER:

That is strange, trees on the same property, one losing its leaves and the other two doing fine. About all we can do is give you some questions to ask yourself to try to find the solution. Chilopsis linearis (desert willow) is an excellent plant for the Tucson area, adapted to the arid heat and soils.

First, you need to consider what, if any, change there has been in the environment of the tree involved. Is it a recently planted tree? In the very intense heat and drought the entire Southwest is suffering, transplant shock would be high on the list of possibilities, particularly if the tree was planted after hot weather began. We recommend that trees be planted in the late Fall or early Winter in the Southwest. the tree is semi-dormant then, and can cope much better with the heat in the Spring when it has had time to develop its roots. 

Have the leaves begun to drop suddenly, are there dead leaves on the ground? How is the drainage of the tree? The desert willow is considered a good candidate for canyon sides and prevention of erosion, because it doesn't need much water, but it does need good drainage. Water standing on the roots of this tree could be causing the problem, just as surely as failure to get enough water. If the tree is in a different soil or drainage situation than the two healthy ones, that should be considered right away. If you water the tree, and water stands on the surface, this probably means you do not have good drainage. You can try to work a little compost in around the roots, and then cover the roots with shredded bark mulch, which will both shade the roots, hold in moisture without water standing on roots, and as it decomposes, continue to contribute to the amending of the soil.

If either of those first two situations seem to be the problem, we suggest treating it as transplant shock. Trim off the upper 1/4 to 1/3 of the limbs (yes, flowers and all). Do what you can to improve the drainage, and then make sure the tree is getting adequate moisture, even if you have to run a hose to it. No fertilizer; native plants don't need fertilizer, they can get their nutrients from the soil they are accustomed to.

To consider the ants you have observed, about the only ant that can remove virtually a whole leaf and make off with it is the leafcutter ant. Read this article from San Juan's The Lurker's Guide to Leafeater Ants, What are leafeater ants? If you can't find a trail or an anthill and don't observe the leaves being carried away, it's not likely that's the problem.

Most insect pests tend to make holes in leaves, not carry them off. We are going to give you references to websites about some common leaf predators, aphids, spider mites, whitefly and thrips. Examine your tree for clues to those insects  being present and the websites will also have control suggestions.

Aphids- University of California Integrated Pest Management

Thrips - University of California Integrated Pest Management

Whitefly -  University of California Integrated Pest Management

Spider mites -  University of California Integrated Pest Management

These insects are all considered not particularly dangerous to the desert willow; however, a tree already in bad condition for some other reason is an easy target for damage from insects and disease. Our suggestion is that you examine your tree, try to determine what is wrong, and if you still don't have the answer, get in contact with the University of Arizona Cooperative Extension Home Horticulture Office for Pima County. They are probably going to ask you the same questions we have and, being closer to the situation, hopefully will have suggested solutions.

Pictures from our Native Plant Database Image Gallery


Chilopsis linearis

Chilopsis linearis

Chilopsis linearis

Chilopsis linearis

 

 

 

 

More Pests Questions

Western soapberry dropping leaves in San Antonio
June 03, 2013 - My Western Soapberry tree (China berry?) Suddenly started dropping full, perfectly healthy green, leaf units. Now half the tree is turning yellow. There is a second tree in the yard not far from this ...
view the full question and answer

Oaks emitting substance in Lakeway TX
August 14, 2012 - We have two large oak trees in our yard that are emitting a clear, very sticky, non-fragrant substance. The leaves are beginning to be covered as is our deck. Bees are now attracted and I am worried ...
view the full question and answer

Fungus gnats on house plant in Edwardsville IL
July 16, 2009 - I recently purchased a Trailing Perennial Plant, and I am seeing a lot of gnats flying in my house. Could this be the problem?
view the full question and answer

Galls on live oak tree in Austin
December 12, 2013 - I live in Austin, and have a 13 year old live oak in my yard. It has developed little spheres, kind of like green peas, on the underside of the leaves. What is it? Is it harmful? Is there somethin...
view the full question and answer

Insects on yucca from Ft. Worth TX
April 05, 2012 - I have a plant labeled Yucca Soft Leaf recurvifolia that I planted about 5 years ago,& was beautiful until last summer when it became infested with thousands of fast, tiny, dark insects. I sprayed wit...
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.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center