Scientific Name
Chilopsis linearis ‘Bubba’
Desert willow is a small tree native to Arizona, California, New Mexico, Texas and much of Mexico. Its cold hardiness is often stated as minus 10°F, which is considerably lower than what is experienced in most of its native range. Even that level of cold tolerance might make it seem like a risky choice for our area, though it would clearly be at home in our dry climate and hot summers. We are optimistic about this tree because the Denver Botanic Gardens has successfully grown several different desert willow cultivars for many years.
The ‘Bubba’ cultivar was originally found in Texas. It is noted for its bright magenta flowers, which begin blooming in midsummer and continue for at least a month, and possibly into September. The growth habit of the cultivar is upright, and it can be projected to reach at most 20 feet in height, given the infertile soil where it is planted and the likelihood of more xeric conditions in the future. The trees along this ridge surrounding a stormwater detention pond were selected for their drought tolerance. They are receiving additional irrigation initially to help them become established and will eventually survive on little more than our annual precipitation.
The leaves of ‘Bubba’ are willow-like, but the plant is not related to true willows — a confusion sometimes caused by common names. Instead, the Chilopsis genus is closely related to the catalpas, which becomes clear when comparing the similar flower shapes and long, hanging fruits of this tree with those of catalpa species. In fact, some botanists have proposed changing the genus name to Catalpa linearis.