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
Not Yet Rated

Wednesday - July 20, 2011

From: Arlington , TX
Region: Southwest
Topic: Diseases and Disorders, Shrubs
Title: Leaves on yaupon holly turning brown/black
Answered by: Nan Hampton

QUESTION:

Arlington TX Yaupon Holly has leaves on stems closer to the bottom of the plant and moving up that are turning brown/black. Is this a disease, over/under watering? There is black gummy soil, but it has been so hot and dry. The plant is in full sun during afternoon.

ANSWER:

There are molds (e.g., sooty mold) that blacken leaves on hollies such as Ilex vomitoria (Yaupon holly) as well as other landscape plants.  The mold forms on secretions of plant sucking insects such as aphids and mealybugs.  If it is sooty mold, though, you probably can recognize it fairly easily and it will wash off.   My strong conviction, however, is that this is a result of the extreme heat and drought that Texas is undergoing.  You can visit the U. S. Drought Monitor map to see that most of Texas is in "extreme" or "exceptional" drought conditions.  I don't know how much and how you are watering the tree, but when you do water the soil needs to get a thorough soaking—the equivalent of an inch or more of rain.  (The Texas Forest Service recommends 1-4 inches of water every 10 days.  Use a rain gauge or some sort of container under the sprinkler pattern to measure it.) This will insure the water seeps deep into the soil and it will reach the plants roots there and keep them from growing toward the surface.   Also, the roots generally grow out to at least the same distance as the spread of the tree—the drip line—so watering with a soaker hose at the drip line is an efficient way to get the water to the roots.  Be aware that it takes longer to deliver 1 or 2 inches of water using the soaker rather than a sprinkler.  Mulch spread around the tree can also help to hold in the moisture.  Here is an article, Mulching Trees and Shrubs, from North Carolina State University with good tips on mulching and here is an article from our website, Helping Plants Handle Summer Heat.

Of course, overwatering can be harmful to trees, too, with many of the same symptoms of yellowing and dying leaves.  If the soil you describe as "black gummy" is always wet and gummy then you probably are overwatering.  If your soil is always damp more than 4 or 5" down (use a screwdriver or similar sharp instrument to push into the ground), then you are watering too much.   Here is a an article, Watering Trees and Shrubs, with more information from the University of Arizona College of Agriculture & Life Sciences Cooperative Extension Program.

 

More Shrubs Questions

Denying cows access to flowers through fence
March 20, 2008 - What flowers can I plant that cows will not eat? They stick their heads through the fence and eat anything they can reach. I would like to plant something in the fence row that will not hurt the cows...
view the full question and answer

Looking for plants for phytoremediation in Columbus, TX
May 27, 2015 - Hello! I am looking for native Texan phytodegrading/rhizodegrading plants (basically I want phytoremediating plants that could be left in place and not have to be removed/disposed of after they had ta...
view the full question and answer

Problems with Indian Hawthorn in Richmond TX
February 19, 2010 - I have a lot of Indian Hawthorne plants. I have noticed over the last couple of years that sporadically one will develope a brown area that looks like it was burned or had gasoline poured on it. The...
view the full question and answer

Removal of honeysuckle bushes from Coaldale Alberta Canada
July 30, 2010 - I have 2 honeysuckle bushes that I want to get rid of. I am wondering if Honeysuckle bushes have very deep roots (are they hard to dig out?) I am 70 years old and didn't know if I'd be able to dig ...
view the full question and answer

Shape of common ninebark in Canton MI
April 24, 2010 - I have planted one center glow ninebark in a triangular area in between my front walk and driveway. It looks a little odd just having one plant, but I originally did this b/c of the mature plant heig...
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