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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.

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Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

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Thursday - April 05, 2012

From: Phoenix, AZ
Region: Southwest
Topic: Diseases and Disorders, Trees
Title: Texas wild olive tree
Answered by: Ray Mathews

QUESTION:

I live in the Phoenix area. My Texas wild olive (Cordia boissieri) is about 5 years old, about 12 feet tall and has beautiful blossoms all year long. However, this past year (through all seasons) some of its leaves developed yellow/brown spots and other leaves are completely brown and falling off. I am not able to find much information on the diseases of this plant. Might this be a lack of N2? a mold? overwatering? ???? Any guidance you might be able to provide would be appreciated. Thank you.

ANSWER:

The wild olive tree Cordia boissieri (Mexican olive) is an evergreen native only to Texas in the U.S.,  but also to several states in northern and southern Mexico, including Coahuila, Nuevo Leon, San Luis Potosi, Tamaulipas, and Veracruz, per the following Agricultural Research Service, Germplasm Resources Information Network link. This rare small tree is reportedly ideal as an ornamental for confined areas. It is drought tolerant and insect and disease pests are generally of no concern. Birds and other wildlife feed on the fruit. It blooms in late May through early June.

However, since Cordia boissieri isn’t native in Arizona , it may be the wrong plant for Arizona. The symptoms you are observing may be due to mold or overwatering. We don't believe that nitrogen deficiency is the problem.

Bill Britt’s garden website offers the possibility of frost as an immediate cause, but the earlier browning does not follow the description for these symptoms?

We believe that you need someone who can look at the plant, and make an informed assessment. For that we suggest you contact the folks at the Maricopa County Office of Arizona Cooperative Extension for some help closer to home.

 

 

 



 

From the Image Gallery


Mexican olive
Cordia boissieri

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