Wildflower/Perennial · Sonoran native
Yellow Bells
Tecoma stans · Bignoniaceae
Also called: Esperanza, Yellow Trumpetbush, Yellow Elder, Trumpet Flower, Arizona Yellow Bells (var. angustata)
Yellow Bells (Tecoma stans) is a low-water wildflower/perennial native to the Sonoran Desert region well suited to Tucson and the low desert. It thrives in full sun, with a fast growth rate.
Yellow Bells at a glance
- Water use
- Low (established)
- Sun
- Full sun (tolerates light afternoon shade but blooms best in full sun)
- Mature size
- 4-6 ft H x 4-5 ft W (native var.); to 8-12 ft+ for tropical/hybrid forms
- Growth rate
- Fast
- Bloom
- Bright lemon-yellow, trumpet-shaped flowers in showy clusters, Spring through fall (roughly April-November), heaviest with summer monsoon warmth and moisture
- Cold hardiness
- Root-hardy to about 20-25 F (USDA zones 8-11); freezes to the ground below ~25 F and resprouts vigorously from the base in spring. Top growth damaged by frost.
- Soil
- Well-drained sandy, gravelly, or loamy soils; tolerates rocky and alkaline soils. Dislikes waterlogged soil (can develop root/Texas root rot in heavy formerly-agricultural soils).
- Native range
- The narrow-leaf Arizona Yellow Bells (Tecoma stans var. angustata) is native to southern Arizona, New Mexico, Texas, and Mexico; the broader species ranges through the American tropics. In Tucson the native variety occurs on rocky desert slopes and foothills.
- Best used as
- Flowering accent or informal hedge/screen, Pollinator and hummingbird garden, Container plant, Foundation and border shrub, Mass plantings for summer color
- Wildlife
- Flowers strongly attract hummingbirds, butterflies, and native bees. Not a host plant of note, but a prolific nectar source.
- Toxicity
- Generally regarded as low toxicity / non-toxic in landscape use; not on major poisonous-plant lists for pets, though as with many plants ingestion is best avoided.
How to grow Yellow Bells in Tucson & the low desert
Watering
Drought tolerant once established but flowers far better with regular deep irrigation through the warm season—roughly every 7-10 days in summer. Reduce watering in winter; avoid soggy soil.
Fertilizer & nutrients
Light feeder; an application of balanced or bloom (slightly higher phosphorus) fertilizer in spring and again in midsummer supports heavy flowering. Avoid heavy nitrogen, which favors foliage over blooms.
Pruning & care
Deadhead or shear spent flower clusters (and the bean-like seed pods) to prolong bloom. Cut back hard after frost or in late winter to remove damaged wood and shape; it rebounds quickly.
Notes
One of the longest-blooming, most reliable summer-flowering plants for the Tucson low desert. Use the native var. angustata for cold/drought toughness and a more shrub-sized habit; tropical and 'Gold Star'/orange-flowered Tecoma hybrids grow larger and are more frost-tender. Often treated as a perennial/dieback shrub because it freezes back.
Sources: AMWUA 'Landscape Plants for the Arizona Desert'; Arizona Municipal Water Users Association / Water - Use It Wisely; Arizona State University (Arid Zone Trees / VPM plant files); Lady Bird Johnson Wildflower Center