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.

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?

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

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

rate this answer

Not Yet Rated

Thursday - April 23, 2009

From: Fort Worth, TX
Region: Southwest
Topic: Compost and Mulch, Diseases and Disorders, Shrubs
Title: Yellowing leaves on yaupon in Ft. Worth
Answered by: Barbara Medford

QUESTION:

I planted a Pride of Houston Yaupon Holly in January in full sun. It is blooming little white flowers right now for spring, but a lot of leaves are turning yellow. Do you know what is causing this? Thank you.

ANSWER:

"Pride of Houston" is a trade name for Ilex vomitoria (yaupon). It may have been bred from selections that did better in the more acidic, sandy soils of East Texas. This USDA Plant Profile map does not show yaupon growing in Tarrant County. That doesn't mean it won't, it just means it is not native to that part of the state. We are guessing that the yellowing leaves are the results of chlorosis, which is the yellowing of leaf tissue due to a lack of chlorophyll. Possible causes include poor drainage, damaged roots, compacted roots, high alkalinity and nutrient deficiencies in the plant. The best way to remedy this problem is in improving the drainage around the roots and making the soil nutrients more available to the roots. The soil in Ft. Worth is pretty alkaline, and amending the soil with compost or some other organic material is the best way to unlock those nutrients. You can begin by working as much compost as possible into the soil around the yaupon, and continuing to add compost periodically. Use either the compost or a shredded hardwood mulch to mulch the root area. As this decomposes, it will continue to improve the soil texture, and permit the roots to access the trace elements, especially iron, that they need to get back the green in the leaves. You didn't say what the light exposure on your plants is, but the yaupon does best in part shade, which we consider to be 2 to 6 hours of sun a day. The amount of light a plant is getting can also affect leaf color.