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Thursday - October 18, 2007

From: San Angelo, TX
Region: Southwest
Topic: Diseases and Disorders, Shrubs
Title: Nutrient imbalance in Tecoma stans
Answered by: Jimmy Mills

QUESTION:

I have two Tecoma stans on the north-east side of my yard. They have grown very tall (5') but have not bloomed all summer. Last summer they bloomed profusely. Any idea what the problem might be?

ANSWER:

Tecoma stans (yellow trumpetbush) aka Esperanza or Yellow Bells is a popular landscape plant that is native to Texas and Northern Mexico, and the cultivar "Gold Star", developed by a plant breeder in San Antonio, TX, has become a favorite in Texas due to its abundant flower production and its shorter height.

Since you had profuse blooms last summer, but none this summer, the question to ask yourself is what am I doing differently this summer? Flowering is a complex process that is influenced by several factors including amount of sunlight, amount of water, and nutrient balance, particularly the nitrogen to phosphorous (N/P) ratio. Unless you have transplanted the Tecoma or have had an unusual amount of rainfall, you can probably eliminate the first two. Austin has had a really wet summer, and the Tecoma here are blooming spectacularly.
That leaves nutrient levels. If you fertilized in the spring with a fertilizer that had higher nitrogen content relative to phosphorous, this may be your problem. I'm including links to Texas A&M and Penn State that do a great job of explaining the N/P ratio and its effect on flowering.

You might also check to make sure that there aren't any insects that are attacking the immature buds.

From the Image Gallery

Yellow bells
Tecoma stans