Best if planted in full sun and watered occasionally but can tolerate light shade where it better tolerates lower irrigation regimes. It is cold hardy to the mid-20s° F and can resprout if frozen to the ground. A large shrub that adds cheery orange color to the garden and can also be trained up as a small tree.

This plant is thought to be a hybrid between the central Mexican Tecoma stans forma velutina and the South African Tecoma [Tecomaria] capensis. Though this hybrid does not have leaves as such, Tecoma stans forma velutina has foliage that is more pubescent, which distinguishes it from the typical wide ranging Mexican variety, Tecoma stans var. stans and the more northerly variety, T. stans var. angustifolia, which ranges into Arizona, New Mexico and Texas. In all respects this hybrid is smaller growing, of finer texture and with orange flowers compared to the yellow flowered Tecoma stans. This hybrid was attributed to Edwin Smith of Clifton Nursery in Walkerville, near Adelaide, Australia and noted as being developed in 1882 and later named for him by the Horticultural and Floricultural Society of South Australia in 1883 but the official description is listed as being in 1893 in Gardeners Chronicle by William Watson, the curator at Kew.

That this plant was in early cultivation in the US is evidenced by Dr. Franceschi recording it growing in Santa Barbara in his 1895 survey that he self-published that year as Santa Barbara Exotic Flora: A Handbook of Plants from Foreign Countries Graown at Santa Barbara, California and Liberty Hyde Baily's listing in his 1902 Cyclopedia of American Horticulture (predecessor to Hortus) who noted it was "supposed to be a hybrid between Tecoma mollis (an older name for Tecoma stans var. velutina) and Capensis". This plant has in the recent past also been called Tecoma 'Mystery Orange' and Tecoma shirensis. Adding additional confusion about its parentage is that most recent botanical references list the valid name of Tecoma capensis as Tecomaria capensis (it has gone back and forth), which would make this an intergeneric hybrid. There is a beautiful big specimen in the middle of Alice Keck Park Memorial Garden, in Santa Barbara. Our cuttings originally came from this plant, which we have been growing since 1980, first as Tecoma shirensis and later as Tecoma 'Smithii' and finally since 1995 as Tecoma x smithii. 

This information about Tecoma x smithii displayed is based on research conducted in our horticultural library and from reliable online resources. We also will relate observations made about it as it grows in our nursery gardens and other gardens we have visited, as well how the crops have performed in containers in our nursery field. We will also incorporate comments that we receive from others and we welcome hearing from anyone with additional information, particularly if they can share any cultural information that would aid others in growing it.