Ask Mr. Smarty Plants

Tecoma stans (yellow trumpetbush), a tough semi-desert plant, is native to Texas and New Mexico but not to the Houston area, according to this USDA Plant Profile. However, you say yours has been growing fine for the last 10 years,, so we have to ask what in the environment has changed to cause the growing habits of this plant to change? Our first suspicion is the Miracle Gro you have been applying. Not that there is anything wrong with the product, but the whole point in growing plants native to an area is that they do not need fertilizer, they can get the nutrients they need naturally from the soil. The second possibility is that it is getting too much water. Even though Houston is presently in a drought situation, one area's "dry" is another area's "wet."  Although your plant has been growing in the same place for ten years, it is accustomed to alkaline soils and your soils are very likely acidic. We have had several questions about stunted leaves in various situations, and the best we can tell is that this is a way a stressed plant reacts to conditions it is not able to handle very well. 

Here are our suggestions for your plants. Make sure the drainage is good. Roots standing in water can kill a desert plant like this. Reduce the water it receives gradually, and do not fertilize. No plant which is stressed should ever be fertilized. This winter, cut the plant back to the ground, it is easily able to withstand this, and should come back stronger next spring.  Remember this plant needs full sun; if it is in partial shade, that could be contributing to the problem. Try to improve the drainage and the accessibility of trace elements in the soil by working compost into the area around the roots. Mulch the root area, but don't use pine bark or pine needles to do so, even though they are more readily available in the Houston area. Materials from pine trees will only add to the acidity of the soil. 

Finally, you may have to consider that the Tecoma stans (yellow trumpetbush) is reaching the end of its normal life span. We could not find any references stating how long this plant is expected to live, but it is expending an enormous amount of energy putting out those huge beautiful yellow blooms all summer, and it could just be aging. After you have tried the suggested fixes, if there is no improvement, you might consider replacing the plants. If you do so, start out with them in the right place, with composted soil and in the sun. 

Tecoma stans

Tecoma stans

Tecoma stans

Tecoma stans