At first glance the name Desert
Willow seems like a contradiction in terms. Desert
Willow (Chilopsis linearis) is not a true willow. Many
people have attributed the name to the long (2" to 5"),
slender, glossy green leaves that typically grow towards
the ground. The leaf canopy has a weeping, willow-like
appearance. Much of the literature refers to Chilopsis
as a large shrub to small tree growing to 15' to 30'
tall with spreads of 10' to 15'. The references to
Chilopsis being a large shrub may relate to the tree
growing in dry native desert conditions with very
limited or sporadically available water. In landscape
settings, where trees are regularly watered and
fertilized, Chilopsis grow to the stature of most other
desert trees.
When incorporating Desert Willows
into landscape designs architects should consider them
medium sized mature trees that will occupy considerable
space in the landscape. Chilopsis is an excellent accent
tree when used in desert designs. Trees produce filtered
shade that does not inhibit flowering of understory
plantings. Young trees require regular pruning to
develop and encourage graceful single or multi-trunked
specimens. Without pruning, trees can look shaggy with
thick leaf canopies and branches extending to the
ground. Trunks are a slightly roughened gray- white and
contrast nicely with the bright foliage and flowers.
Desert Willows are found in all
the deserts of the southwest US and northern Mexico.
Trees are found from 1500' to 5000' elevations, usually
along streams or basins where rainfall collects. Trees
are drought and winter deciduous, generally drop leaves
in late November, and hardy to 10 degrees F. Established
trees can survive on natural rainfall but irrigated
trees grow more rapidly and produce more flowers and
foliage providing greater shade. In summer months, young
trees can be irrigated every other week. For optimal
growth and flowering, mature trees should be deep
watered every 3 to 4 weeks. In the landscape, Desert
Willows grow best in well drained soils and full sun
exposures.
Chilopsis is one of the few desert
tree species that produces flowers throughout the summer
months. Trees produce beautiful, slightly fragrant,
orchid-shaped flowers from early spring to fall.
Chilopsis flowers also attract and provide nectar for
hummingbirds. For many years growers and Universities
have been selecting and breeding Chilopsis varieties for
larger, brighter colored flowers. Depending on the
variety, flower color varies from off-white to dark
lavender. Flowers mature to produce 6" to 8" tan pods
that spilt open to release seeds. Pods often do not drop
from the tree and can be unsightly, particularly when
trees are dormant. Pods can be pruned off during winter
months.
Seed pods and cast flowers can be
a litter problem in some settings. Desert Willows are
well adapted to both lawn and traditional desert
landscape settings. They are used as summer color accent
trees, individual specimens, as screen plantings
(usually left unpruned) or in groupings. Chilopsis bring
summer color, cold hardiness and a unique lush look to
arid landscape designs.