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

Thursday - June 20, 2013

From: Bellaire, TX
Region: Southwest
Topic: Diseases and Disorders, Pests, Trees
Title: Changing colors on Mexican Plum trees from Bellaire TX
Answered by: Barbara Medford

QUESTION:

The leaves on my Mexican Plum tree have recently started turning yellow/brown and the veins in leaves are red. Is this a watering issue or disease issue? Mites are on the leaves. This has been a rapid change over the past month. I recently sprayed for the mites and will continue to do so for the next couple of weeks.

ANSWER:

According to this USDA Plant Profile, Prunus mexicana (Mexican plum) grows naturally in Harris County, so the soil, climate and rainfall should be appropriate for it there. The problem sounds to us like chlorosis, a condition usually resulting from some imbalance in the soil.

Please read this article from the University of Illinois Extension on chlorosis. Note the comment that the presence of chlorosis is often due to high alkalinity in the soil. We could not find out if your soil in  Harris County is particularly alkaline, but we usually expect East Texas soils to be more acidic.

Among the steps we would recommend are to use some sort of iron supplement, not too much, as native plants do not ordinarily care for fertilizer. Water less, because it's possible the main problem is lack of drainage in soil where the plants are growing. Watering once a week should be adequate.  Finally, using a good quality organic mulch, spread the mulch over the root area without allowing it to touch the trunk area. This will protect the roots from heat and cold and, as the mulch decomposes, will add some material to the soil to assist in drainage.

In answer to your question on whether this is a watering issue or a disease issue, here are the growing conditions for this plant from our webpage on Prunus mexicana (Mexican plum):

"Growing Conditions

Water Use: Low
Light Requirement: Sun , Part Shade
Soil Moisture: Dry , Moist
Cold Tolerant: yes
Soil Description: Dry to moist, well-drained soils. Sandy, Sandy Loam, Medium Loam, Clay Loam, Clay, Limestone-based"

As you can see, this plant is adaptable as far as soils are concerned, but does not like wet feet. You get more rain in Harris County than we do in Central Texas and if you are also watering, the roots could be standing in water, which they definitely do not like.

Next, on the subject of mites. Please read this article from the University of Missouri Extension on Aphids, Scale and Mites on Home Garden and Landscape Plants. In particular, note that these pests often will attack plants that are already under stress; for instance, if the soil in which the tree is planted does not have good drainage. Also, pay attention to the reminder to carefully read and follow instructions on the use of pesticides. The pesticide you are spraying could very well be killing instead the natural predators of the pests on your plant- ladybugs, for instance.

 

From the Image Gallery


Mexican plum
Prunus mexicana

Mexican plum
Prunus mexicana

Mexican plum
Prunus mexicana

More Diseases and Disorders Questions

What are the green round growths on the edges of my oak leaves in Fairfax, OK
May 21, 2013 - round growths on the edge of oak leaves. ranging in size from a pearl to a lime. ranging in color from pale green to lime green. hollow, small ones appear to contain one small gnat sized seed. the la...
view the full question and answer

Care of Ecuadorian penco century plant
December 17, 2007 - I was recently given a Penco, Century plant from Ecuador. It doesn't seem to be doing well. Two of the leaves have turned dark, then yellow, and died completely. Five remain, one seems to be dying as...
view the full question and answer

Treating scarred Gum Bumelia from Lampasas TX
June 05, 2013 - We have a very old Gum Bumelia with a scarred open tree trunk. In the past concrete was used to fill the scarred trunk. What is the acceptable method of helping the tree. More concrete or using blac...
view the full question and answer

Migrating Turkey tail fungus in garden in Austin, TX
November 25, 2014 - I have turkey tail fungus that has migrated from a rotting elm tree stump to a part of my garden that has a healthy wax myrtle tree and other native shrubs, but no rotting tree stumps. Its presence h...
view the full question and answer

Full Sun, Wind-Tolerant Shrubs and Vines for Steep MN Hillside
June 26, 2013 - My neighbor and I share a very steep, large (in total almost 200 ft. wide) west-facing hillside in Excelsior, MN on Lake Minnetonka. We both have a flat grass area at the bottom so the hillside does n...
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