Native Plants
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.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.
rate this answer
Monday - February 25, 2013
From: Plum, TX
Region: Southwest
Topic: Non-Natives, Diseases and Disorders
Title: Black Sooty Mold on Bay Tree
Answered by: Anne Van Nest
QUESTION:
I have a large bay tree and all the leaves are covered with a black mold-like substance on the top part of the leaf. Under each leaf are some black/brown spots. I have washed the leaves with soap and water using a wash cloth. This cleans the leaves some but this stuff is stubborn. I really do not want to hand wash 1000+ leaves. I have tried fungus sprays, mold spray, and high pressure washing with just water. Nothing seems to help. All the new growth is getting the same gunk. Help!ANSWER:
Sorry, bay laurel trees (Laurus nobilis) are a little out of our line since they are native to the Mediterranean. The Lady Bird Johnson Wildflower Center, home of Mr. Smarty Plants, is committed to the growth, protection and propagation of plants native not only to North America but to the area in which they are being grown. In Texas, this is Texas A&M. Below though are links to several websites which we believe have the information you are looking for. Look at the Texas A&M AgriLIFE Extension web page on bay laurels.
Your plant symptoms though are similar to what sooty mold does when it attacks some native plants. The sooty mold grows on the honeydew that is excreted by small soft-bodied aphids or scales that suck sap from plants. In your case there is a laurel aphid that attacks bay laurel trees and excretes a sticky, sugary substance that drips down onto the tops of lower leaves. Soon thereafter, a black, mold grows on the sugar. The sooty mold blocks the light to the leaf and weakens the plant.
Look for small pale green insects (aphids) on the new growth or small round bumps (scale) to find the ultimate culprit of the problem. Once you have determined the honeydew cause (and solved this problem), you will be able to get your mold under control. For more information look at this ehow article on bay laurel tree problems.
More Diseases and Disorders Questions
Mountain laurel with fasciation
July 24, 2014 - My Texas Mountain Laurel bush has developed several "crested branches." What causes this, is it harmful & how do I get rid of them???
Thank you!
view the full question and answer
Older leaves yellowing on Savannah holly in Dallas
May 01, 2009 - I planted a Savannah Holly in Dallas, TX in the Fall of 2008. It has new growth and some white buds all over it, but some of the older leaves are turning yellow and dropping off. Is this normal?
view the full question and answer
Death of mature Eve's necklace in Fredericksburg, TX
July 12, 2010 - A friend mentioned his mature Eve's necklace had died this year. The next day I walked past my own mature Eve's necklace(about 5 years old)and it was dead! What could have happened? Thanks.
view the full question and answer
Non-native red-tip photinias dying in San Antonio
August 20, 2009 - A 17 year old Red tip Photinia in a hedge shows signs of dying. The main stalks are quite large and offshoots from two of the stalks have brittle, drooping leaves. The center of the plant looks norm...
view the full question and answer
Shy blooming non-native Crape Myrtle, in Littlestown Pennsylvania
July 25, 2011 - My Crape myrtle has been planted about three years, and reached a height of about 4'. It blooms late July and for the past two years, has only had one or two blooms on it. I have a lot of buds whic...
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |