Ask Mr. Smarty Plants

We found an online article about Hamelia patens (scarletbush) that specifically talks about it thriving in Laredo. This Texas Cooperative Extension site PlantAnswers.com praised the plant as being almost immune to drought and loving heat. Another article from the Horticulture Department of Texas A&M by Dr. William C. Welch on Firebush comments that even in South Texas, it freezes to the ground and resprouts in early Spring. 

All our sources recommended trimming the bush heavily in February. Flowers are on new growth, so this will encourage blooming. The same sources say it can be trimmed to the ground and will still come back. However, it apparently doesn't really flourish until it gets very hot, and requires little water once established. Dr. Welch, in his article, also comments on the plant as being "typically a 4 to 5 foot mound."  We noted the existence of a cultivar called "Compacta." We're wondering if this might be what you have, in which case, you shouldn't expect it to grow very tall. Another possibility could have to do with the watering the plants are getting. They require very good drainage, and if you are watering them regularly and the soil is not draining well, it could be causing some problems. Finally, these plants do best in full sun, although they will tolerate some shade. 

We recommend that you watch for drainage problems, trim it back in the late Fall, and accept a potential height of no more than 5 ft.  It still will make a beautiful garden, and your hummingbirds will love you. Here is a page of images of Hamelia patens.