Desert Willow
Chilopsis linearisSCS PLANT CODE : CHLI2
COMMON NAMES : desert willow, desertwillow, flowering willow, flowering-willow, willowleaf catalpa, desert catalpa, catalpa willow, false-willow, bow willow, mimbre, Flor de Mimbre, jano
TAXONOMY : The currently accepted scientific name of desert willow is Chilopsis linearis (Cav.) Sweet [17,27,49].
Chilopsis linearis (Cav.) Sweet
ssp. linearis
var. linearis - Chihuahuan Desert
var. tomenticaulis Henrickson - eastern Mexico
ssp. arcuata (Fosberg) Henrickson - Sonoran and Mojave Deserts
GENERAL DISTRIBUTION :
Desert willow is distributed from southwestern and Trans-Pecos Texas west to extreme southwestern Utah, southern Nevada, and southern California [21]. It is also found in northern Mexico.
Wildlife: Various species of birds eat desert willow seeds [12,46]. Hummingbirds are attracted to the showy flowers and feed on the nectar [3,12]. Mule deer eat small quantities of the leaves and fruit [34].
NUTRITIONAL VALUE : The sucrose in desert willow nectar is a good energy source for bees and hummingbirds [3].
COVER VALUE : Desert willow provides nesting sites for desert songbirds and cover for other wildlife species [20].
GENERAL BOTANICAL CHARACTERISTICS : Desert willow is a large deciduous shrub or small tree that may grow 10 to 30 feet (3-9 m) tall, and often has a leaning trunk and an open, spreading crown [18,25,46]. Basal diameter of the trunk rarely exceeds 5 inches (12.5 cm) [14]. The dark brown bark is very thin, up to about 0.25 inch (6.3 mm) thick [14]. Pale green willowlike leaves are about 5 inches (12.5 cm) long and less than 0.5 inch (1.25 cm) wide with smooth margins [27,46]. The pink to light violet flowers are 1.25 inches (3.2 cm) long and wide, and occur in clusters up to 4 inches (10 cm) long at the end of the twigs [25]. The fruit is a narrow, elongated two-celled podlike capsule 4 to 10 inches (10-30 cm) long [48]. First year twigs are green but later turn gray to reddish-brown [46].
REGENERATION PROCESSES : Desert willow reproduces sexually by producing abundant seed. Flowers are primarily pollinated by numerous species of bees and hummingbirds [3]. Large numbers of flowers are produced continuously over several weeks [31]. Desert willow flowers are self incompatible. Fruit set may be limited by insufficient amounts of outcrossed pollen and by inadequate movement of pollinators between trees [31]. Fruit production does not appear to be limited by inadequate moisture, probably because plants are primarily found along washes.
Several 0.33 inch (8 mm) long, light brown, oval seeds are encased within a two-celled capsule [26]. Seeds have a fringe of soft white hairs at each end which aid in wind dispersal [26,30]. Seeds do not display dormancy, and probably only remain viable until the spring following dispersal [26]. There are between 50,000 and 100,000 seeds per pound (110,200-220,400/kg) [26,45]. Germination has been reported between 40 and 60 percent [45]. Commercial seed has shown 92 percent purity and 87 percent soundness [26].
Sprouting: Following damage to the above ground portion of the plant, such as by fire, most plants regenerate by sprouting from the root crown [41].
SITE CHARACTERISTICS : Desert willow primarily occupies dry washes, intermittent streams and other water courses, and moist canyons in deserts and mountain foothills [4,16,18,27,35,49]. These sites generally have underground water available year-round. Plants can withstand seasonal flooding quite well, and often occupy the middle of drainage channels, sometimes covering broad expanses in wash areas [10,16].
Soils: Sites are mostly well drained, neutral to basic and mildly saline [48]. Soils are mostly sandy to gravelly alluvium [29,35,48].
Associated species: Common associates of desert washes include blue paloverde (Cerdidium floridum), desert ironwood (Olneya tesota), catclaw acacia (Acacia greggii), smoketree (Dalea spinosa), mesquites (Prosopis spp.), desertbroom (Baccharis sarothroides), netleaf hackberry (Celtis reticulata), littleleaf sumac (Rhus microphylla), Arizona walnut (Juglans major), velvet ash (Fraxinus velutina), spitleaf brickellia (Brickellia laciniata), cottontop (Digitaria californica) and southwestern condalia (Condalia lycoides) [4,10,16,29,31,48].
Elevational range by location:
below 4,000 feet (1,219 m) AZ [18]
below 5,000 feet (1,524 m) CA [27]
below 4,920 feet (1,500 m) UT [49]
SUCCESSIONAL STATUS : Desert willow sometimes invades freshly deposited channel sediments following seasonal water runoff. As plants develop they may trap sediments, leading to the formation of islands within the channel [10].
Desert willow plants are long-lived and help stabilize the banks of water courses. Desert willow is a component of desert wash communities that are somewhat stable.
SEASONAL DEVELOPMENT : Since desert willow is primarily restricted to washes or water courses with available underground water, it is able to maintain a full compliment of leaves during the summer months even though it is not well adapted to high temperatures [4]. Plants are winter deciduous and drop leaves in late fall following the first hard frost [6]. Leaf drop may be photoperiodically controlled, as plants in temperature controlled greenhouses lose their leaves during the winter [6].
Flowering occurs mostly in May and June but may occur later in the summer after rain [46]. Most fruits ripen from late summer to fall, and the capsules persist overwinter [46,48]. Under extremely dry conditions, plants may fail to form fruits [31]. In a wash near Tucson, Arizona, flowering occurred mostly in May and June, and most fruits were mature by September 2 [31].
AUTHORSHIP AND CITATION :
Uchytil, Ronald J. 1990. Chilopsis linearis. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service,
Rocky Mountain Research Station, Fire Sciences Laboratory (Producer).
Available: http://www.fs.fed.us/database/feis/ [2012, October 2].
