Explore Plants

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
    
 

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

Further question on sprouts from holly tree in Surprise AZ
November 16, 2010 - Thank you Barbara Medford for your response to my question about the sprouting holly tree in Surprise AZ. I took for granted that the tree I was talking about was a holly tree. I looked at pictures of...
view the full question and answer

Sticky sap (honeydew) on car
July 10, 2012 - MY CAR IS CONSTANTLY COVERED WITH STICKY SAP. I LIVE IN AN AREA WITH MANY COCONUT PALMS AND OTHER TREES. COULD THE SAP BLOW AROUND EVEN THOUGH I KEEP CHANGING THE PARKING?
view the full question and answer

Wilting stems on beautyberry in Georgetown, TX
August 16, 2009 - Last summer I discovered that a 4-year old beautyberry had one (of many) stems that died. Leaves on this single stem wilted and dried up. This year the same happened to two or three stems. The rest of...
view the full question and answer

Smarty Plants on arborvitaes
March 28, 2005 - Hello, I live in Allentown, PA and have a 7-foot arborvitae shrub in my backyard, planted in the corner of the yard where a wood fence intersects with the brick wall of the garage. I have had ma...
view the full question and answer

Problems for Texas Madrones from Dripping Springs TX
November 15, 2010 - Dear neighbor: I'm blessed with a property with many Texas Madrone on it. I've been trying for a few years to determine what causes apparently healthy trees to suddenly blacken and die. I've con...
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.