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Monday - November 30, 2009

From: Corpus Christi, TX
Region: Southwest
Topic: Compost and Mulch, Diseases and Disorders
Title: Esperanza with rust spots in Corpus Christi, TX
Answered by: Barbara Medford

QUESTION:

I have a young esperanza plant and the leaves have what looks like rust spots all over them. What is the cause of this and what can I do for it? My other larger and older esperanza does not have this.

ANSWER:

Without being able to actually see your plant, about all we can do is give you some questions to ask yourself about the location, soil and age of your Tecoma stans (yellow trumpetbush).

We always begin by looking for pests and diseases that might commonly cause a problem and found, as so often happens, that just about every resource we looked at said this plant was resistant to pests and diseases, had none or was seldom bothered. A nice way of saying they didn't know, either. This University of Florida IFAS Extension website gives more complete information on the culture of the plant. There is always the possibility of whiteflies, aphids or scale defacing the leaves, but none of them are major concerns. And check the sun exposure: this plant requires full sun (6 hours or more of sun daily) or part shade (2 to 6 hours daily).

We know we sound like a broken record, but the weather the last two years has been very unforgiving, heat and drought taking its toll on even hardy desert plants, which Esperanza is. You say your older plant is not showing these signs, which makes us wonder when you planted the newer one. If it was planted during the heat and drought we were still having up until mid-October, it could very well be suffering from transplant shock. In fact, research shows that plants can suffer transplant shock for up to 5 years after the original planting. Even a desert plant will need supplemental watering when there has not been sufficient rainfall, and the Esperanza particularly needs good drainage; that is to say, no water standing on the roots after it finally gets some rain, or even from a sprinkler system.

Your plant is about to go into dormancy anyway. In Corpus Christi, it probably won't get cold enough to cause the plant to die back to the ground, but a good trimming back in early Spring will not only initiate more vigorous growth and blooming, but is also the treatment we usually recommend for transplant shock. Be sure and check the drainage; working some compost into the dirt around the roots and mulching the roots to add more heat and cold protection will also help.