The Genus Choisya
Family: Rutaceae
The Arizona species are seldom to almost never in the trade, but deserving of a lot more attention. These plants are often called “orange” or “mock orange” and as these names imply, these perennial plants are related to citrus, and their flowers have a similar, pervasive citrus-flower like smell. They can bloom anytime in the warm season, but most heavily after July into fall. They typically grow about 3’ tall spreading a little wider. Rarely they can scramble up other plants and reach up to 6’. The Mexican species can grow taller.
Mexican Orange (Choysia ternata) is in the trade in some parts of the country, and has even naturalized in some places (like Oregon).
Plants are best in afternoon shade in the low desert, and can handle shady locations where other plants won’t thrive. It’s not really known how cold-hardy they are, but certainly for our region, they can grow in almost anywhere but in the highest mountain locations. Moderate to regular water is encouraged, as long as there is good drainage.
The plants are hermaphrodite (has both male and female organs) and are pollinated by Insects. These plants are a fantastic larval host for butterflies—the following species are likely to host on Choisya species where we live:
Western Giant Swallowtail (Heraclides rumiko)
Broad Banded Swallowtail (Heraclides pallas ssp. bajaensis)
Ruby-spotted Swallowtail (Heraclides anchisiades)
Two-Tailed Swallowtail (Papilio multicaudata)
There has been some taxonomic shifting of these plants—what once was a variety of dumosa is its own species now (Choisya arizonica). There are 6 species total of Choisya native to southern North America, from Arizona, New Mexico, Texas and south through most of Mexico.
Santa Cruz Starleaf Orange (Choisya dumosa var. mollis). Photo by Fern Bromley, iNaturalist
Arizona Starleaf Orange (Choisya arizonica). Photo by Matthew Lachiusa, iNaturalist
Palmer's Orange (Choisya palmeri). Photo by Pedro Nájera Quezada, iNaturalist
Mexican Orange (Choysia ternata) has larger leaves. It is native to Mexico. Photo by Hannah Cogger, iNaturalist