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
3 ratings

Sunday - April 03, 2011

From: Wimberley , TX
Region: Southwest
Topic: Diseases and Disorders
Title: Browned foliage on Juniperus ashei in Wimberley TX
Answered by: Barbara Medford

QUESTION:

We are in Central Texas and have native "cedar" juniper trees. One with foliage that looked brown, on close inspection, is covered with white webs. The foliage looks like it is dying. No worms are visible. It is about 15 ft tall and close to oak and other cedars as well as other native landscape plants. Should it be treated? With what, or must it be removed and burned? Guess we need an answer very quickly before it spreads further. Thanks very much.

ANSWER:

Following the "cedar fever" season we have just had, most Central Texans would say "burn it" and use descriptive adjectives we can't repeat in a family website. However, a tree is a tree and Juniperus ashei (Ashe juniper) is native to Central Texas, so we will see what we can find to help you make a decision. Just about this same time last year, we had a similar question from San Antonio. We never came up with an actual answer, but had several links that we think should be helpful. We are just going to copy portions of that answer for you.

Note from Mr. Smarty Plants: After this answer was published, we heard from Eric Beckers, a forestry specialist and got some better information. We are always grateful for technical help from the professionals in the field, and Eric has been especially valuable to the Wildflower Center and to Mr. Smarty Plants.

"I was reading Barbara Medford's March 19 Mr. Smarty Plants response concerning browning junipers in the Wimberley area and I can confirm the cause to be mites (not sure of the species).  I've been hearing about it from Hays County Master Naturalists over the past couple weeks and saw it first hand earlier this week.  You might consider modifying your response and lean even harder towards a diagnostic of mites.  I also saw something like a thrip, but the webbing and mites were obvious.  Barbara's reference to the New Mexico State University site was a good one and NMSU is right on with our own similar issue.  Until it rains we will probably continue hearing about this problem."

You don't ordinarily think of this plant as having problems. More people want to get rid of it than take care of it. Because we are not plant pathologists and, of course, can't see the tree in question, we went hunting on the Internet to see if we could find clues for you. Some of these have pictures, and we will give you a link to a couple of Google Images sites to compare with your tree. The two from New Mexico State University and West Virginia State University were the only mentions of spider mites. One was written three years ago and mentions that the weather had been dry, which helped contribute to spider mite infestation.

If you get the impression that we really don't know what is causing the die-back on your tree, you are absolutely right. After you have read these sites, and compared the symptoms with your tree, we suggest you contact the Texas A&M AgriLife Extension Office for Hays County. They are more likely to be familiar with this problem than we are

Morton Arboretum Juniper Tip Blight "Common disease of junpers in most states east of the Mississippi River."

University of Illinois Integrated Pest Management Phomopsis "This disease could be confused with cold injury or spider mites." Images of Juniper Twig Blight from Google.

USDA Forest Insects & Disease Leaflet Phomopsis Blight of Junipers

New Mexico State University Juniper branches turning brown Blames spider mites.

Washington State University The Trouble with Juniper mentions that too much humidity and moisture can cause this browning, as well as aphids. Images of aphids on junipers from Google.

Of all these, we are most likely to go with spider mites in your case. See this article on Spider Mites from Colorado State University Extension in which whitish webs are observed.

 

 

 

More Diseases and Disorders Questions

What's that sticky stuff on plants under many trees?
August 23, 2010 - Here in Austin, I've recently noticed a sticky film appearing on shrubs, flowers, grass, etc. under many trees. It appears to be coming from the trees under which they are planted. The sticky film ...
view the full question and answer

Theory for live oak shoots from Austin
August 25, 2011 - More on preventing suckers from coming up around live oaks in Austin. I too have been puzzled - why some live oaks have shoots, and not others. Posting here says different varieties have suckers. ...
view the full question and answer

Yellowing of palm tree leaves
May 14, 2008 - I want to know about palm trees. The leaves are turning yellow.
view the full question and answer

Problems with mature cottonwood in Justin TX
September 17, 2012 - I have a very large, 90" circumference, approx 60' tall, cottonwood tree in my front yard that appears to be sick. The trunk splits at about the 4' level into 2 parts. at that split is a 10" wide...
view the full question and answer

Oak roots damaged by ax from Austin
July 03, 2013 - Hello. I am attempting to create my own tiny copy of the Wildflower Center within my yard. I'm using all native, drought tolerant plants. My front yard is full of live oaks. I used a sod cutter la...
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