Hardiness zones
Sunset 12-13, 16, 18-24
USDA 9 (sometimes cold injury in exposed areas, but quick recovery)

Landscape Use: Floral accent, background screen, specimen around large patios and ramadas exemplifying regional or Spanish architecture; best used in oasis and transition landscape designs settings.

Form & Character: Evergreen to partial evergreen large shrub, upright and open, festive, informal, subtropical to tropical

Growth Habit: Vigorous and upright to 15 to 20' but can be easily maintained at 5' to 10'. Hardened stems are very brittle. Cultivars are generally less vigorous.

Foliage/texture: Opposite, pinnately compound leaves on brownish gray stems, leaflets coarsely serrate, stem lenticels and auxiliary dormant buds are obvious; medium coarse texture.

Flowers & fruits: Yellow trumpet flowers in terminal clusters, long narrow bean pods.

Seasonal color: Yellow flowers during all growing season, heaviest in spring and fall.

Temperature: Tolerant, heat loving, but freeze sensitive.

Light: Full sun required, will grows in an loose, open and rangy manner if shaded.

Soil: Yellow bells is tolerant od all Arizona soils except those wit hthe highest degree of alkalinity.

Watering: Yellow bells responds well to regular water and fertilizer applications during summer by producing more vigorous growth and heightened flowering. It will tolerate only moderate amounts of drought.

Pruning: Prune yellow bells hard in the winter to control height and stiffen upright character.

Propagation: Softwood cutting, seed

Disease and pests: In the Phoenix area, Texas and phytophthora root rot fungi occasionally cause sudden plant death, usually only in heavy soils with a former agricultural use history.

Additional comments: This is a great large accent shrub for large spaces. Yellow bells can look sparse during periods of winter cold and high summer heat. T. stans var. angustata (Arizona yellow bells) is a smaller, more fine textured, northern varietal cline from southern Arizona, New Mexico, west Texas and northern Mexicio that is more drought tolerant, but also more susceptible to Texas root rot in most formerly agricultural soils. Other superior cultivars of T. stans in the Phoenix area include 'Gold Star' and 'Sundance', both of which are of smaller size and flower profusely. The cultivar 'Gold Star' was selected by Texas plant breeder Greg Grant from a private garden in San Antonio, Texas. 'Sunrise' is a cultivar that has yellow blooms veined with copper threads. 'Sierra Apricot' is a unique dwarf hybrid cultivar with abundant apricot-colored flowers that grows to about 3 to 4 feet in height with a slightly greater spread. It is a heat tolerant hybrid of T. stans and T. alata

Yellow bells has long been known and used by native Americans of the Southwest and Mexico for bowmaking, bee fodder and medicines. It is considered an invasive plant in Hawaii.