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 - March 18, 2010

From: flagstaff, AZ
Region: Southwest
Topic: Diseases and Disorders
Title: Need help with canker in willows in Flagstaff, AZ.
Answered by: Jimmy Mills


We've got a lot of willows in high altitude desert conditions, irrigated. They've got canker and I want to know if there's anything I can paint on the pruning wounds when I go around trying to remove infected branches. otherwise I'm afraid of the pruning wounds just being new avenues for infection.


You don't mention the kind of willows that you have (there are 55 species of Salix in our NPIN Data Base), but many seem prone to having canker problems.

Lets look at the pruning paint question first, and then I'll provide some links that might helpful in dealing with the canker problem.

In the past, applying pruning paint to pruned branches was generally thought to be necessary to prevent infectious diseases and infestation by insects. The current thought is that in most cases it is not necessary, and that it may cause more harm than good. Here are a couple of links that support that idea.


Tyler Trees

This Bulletin from the  Integrated Pest Management Program of the University of Illinois Extension, and this report from the University of Florida have some good information about canker in willows and the fungus that causes it.



More Diseases and Disorders Questions

More on oak problems in Carrollton TX
April 04, 2011 - Thank you for answering me, I will contact a specialist to see if we can determine the cause. but since writing you we have pulled down a small twig to see the leaf more closely, it is more of a reddi...
view the full question and answer

Problems with recently planted trumpet vine from Worcester MA
October 20, 2012 - Dear Mr. Smarty Plants, I have a question about my recently planted Trumpet Vines. First of all, I live in Massachusetts, zone 6. The soil is perfect for the two vines, which I bought from a local nur...
view the full question and answer

Problems with Blackeyed Susans in Philadelphia
May 26, 2009 - For 8 years I successfully grew Black Eyed Susans in a fairly large area in my garden. For the last two years,almost immediately upon pushing through the ground they develop black spots and then appe...
view the full question and answer

Live oak leaves not dropping from Austin
April 29, 2014 - We had a 65 gallon live oak planted last October. We watered it regularly and it was green all through the winter. In March the leaves started to turn brown but never dropped, as they should have. ...
view the full question and answer

How to treat bark damage on oak tree
November 15, 2011 - I have an oak tree approx. 50 ft., live in austin, texas. the tree has dropped bark about 3-4 ft above ground, in a section of 4 inches by 8 inches, and the tree appears dark where the bark was. is ...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2015 Lady Bird Johnson Wildflower Center