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?

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
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
2 ratings

Sunday - August 03, 2008

From: Springdale, AR
Region: Southeast
Topic: Non-Natives, Diseases and Disorders, Trees
Title: Yellowing leaves on weeping willow
Answered by: Barbara Medford

QUESTION:

We have a 4 year old Weeping Willow, 12+/- ft. tall and this week the leaves are starting to become yellow. This willow is full and robust in appearance, best it's ever looked. We have 2 other Weeping Willows, not as large, but attractive trees, 100ft. north and 100 ft. east. They show no sign of yellow. Could you please advise me? Is this common and should it effect the remaining willows?

ANSWER:

If it's not No. 1, "What's wrong with my weeping willow?" is right up there close to the top of most frequently asked questions to Mr. Smarty Plants. On today's slate, alone, there are three questions. If you search on "weeping willow" in the Ask Mr. Smarty Plants section, you get ten possibilities. The problem is, the question is the wrong question asked at the wrong time. We wish that gardeners would ask "Should I plant a weeping willow?" BEFORE they purchase and plant it. Non-native to the United States, Salix x sepulcralis is a hybrid of a Chinese species (Peking willow) and a European species (white willow), and is said to grow in Zones 5 to 8 in the United States. It is weak-wooded, fast-growing and, therefore, short-lived. It has aggressive roots, can lift sidewalks and interfere with sewer lines, often growing on soil surface, making a problem with mowing. It is susceptible to a number of pests and diseases, and notorious for littering the ground beneath it. See this University of Florida Extension website on Weeping Willows for more information. Also, in case you think we're exaggerating, see this Q&A from North Dakota State University Extension on weeping willows.

The Genus Salix is considered to have intermediate tolerance for flooding around its roots, especially in the growing season. The water on the trunk and roots over an extended period of time can lead to yellowing of the leaves (chlorosis), defoliation, and reduced leaf size. Young trees may be more intolerant of flooding than more mature trees. Chlorosis is also caused by inaccessibility of trace elements in the soil, especially iron, to the roots. This is sometimes caused by poor drainage, meaning too much water is around the roots, or impacted soil from foot traffic or construction. If the two trees that continue to do well are in a more neutral or acidic soil, they are probably able to access the trace elements in their soil. If the tree you are concerned about either has poor drainage or too much water over its roots or is in a more alkaline soil, the lack of trace elements could explain the yellowing leaves. We picked up this information from the University of Florida website referenced above: Rust causes yellow spots on the lower surfaces of leaves and, if severe, defoliation. Rake up and destroy leaves from diseased trees. The North Dakota State website had several references to poplar borers as being a possible cause of yellow leaves.

Most to be hoped for would be that the problem is being caused by poor drainage, etc. preventing the access of iron in the soil. Getting some compost or other organic material into the soil, and even putting some iron tablets into the soil would be the easiest fix. The other possibilities are not something we can diagnose from a distance. If there are borers, you should be seeing some small holes, possibly with a red stain draining from them. If survival of your willows is important enough to you, even after we've given you all the downsides, we suggest you have a trained arborist look at the tree. If some pesticide is called for, the arborist should be licensed to do so in Arkansas. Since Springdale is in two counties, you could also contact the University of Arkansas Extension office at Washington County, or Benton County.

 

More Non-Natives Questions

Problems with yellow lantana in Smoaks SC
June 05, 2010 - My yellow lantanas are about five years old - big and beautiful, but beginning last year, the blooms are small and part of the tiny petals are brown or black. Can you tell me what I can do about this ...
view the full question and answer

Lavender near Austin TX
July 10, 2011 - Are there places to view blooming lavender near Austin in July 2011?
view the full question and answer

Lilac bush roots dangerous to house foundations
August 06, 2008 - Are lilac bushes dangerous to the foundation of a house? There is a lovely white-blooming lilac that grows against the house outside my bedroom window. My ex-husband said that the roots would destro...
view the full question and answer

Competition between Horseherb and Chickweed
July 04, 2014 - Ok, sorry I did it wrong the 1st time!? I live in Houston, and I have chickens! I also have mass amounts of Horseherb, and I want to buy some chickweed seeds and plant it for my chickens! My question ...
view the full question and answer

Mexican species Orbexilum melanocarpum.
January 04, 2013 - This is not a question; just a note to supplement a previous MSP post answering a query about a source for Orbexilum. The "mountain pea" that the original questioner was asking about is the e...
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 | STAFF
© 2015 Lady Bird Johnson Wildflower Center