Someone needs to tell the Urban Forests Ecosystems Institute (UFEI) that their tree location map is missing the desert willow (Chilopsis linearis) that was planted at the Master Gardener Demonstration Garden at Patrick Ranch several years ago.

A project of California Polytechnic State University (Calpoly), the UFEI website is a tree data treasure trove: their individual tree repository, SelecTree, is full of fascinating information about species that grow in our state. A favorite feature of the site is a map that indicates reported locations of each tree species. In Butte County, they map four Chico occurrences of the desert willow: Entler Avenue; East 8^th Street; Kennedy Ave; and East Ave. No mention, however, of our specimen tree on the Midway south of Chico. The East Avenue location probably references the very mature desert willow that grew on the grounds of our local native plant nursery – which has since moved its business to the dry grasslands north of town. Sadly, the tree and all other natives planted on that property were cleared for new construction and a parking lot. In Paradise, the UFEI website shows one desert willow on Foster Ave, although that may have fallen victim to the Camp Fire.

A second great feature on the UFEI website is its registry of California's Big Trees – a description of the largest known individual specimen in the state. Porterville is where you will find the largest desert willow in California. Although the tree normally doesn't top out at over 25 feet, the specimen in Porterville is 40 feet tall, with a canopy spread of 36 feet and a trunk circumference of just over six feet. Pretty big for a tree billed by multiple sources as a “small accent tree” for your native landscaping.

Chilopsis linearis is prized in dry gardens for its showy and fragrant blossoms, which cover the tree in summer, when a number of native bloomers are past their spring glory and entering semi-dormancy to protect against heat and drought. Desert willow, on the other hand, is just getting started, and loves the long hot days of summer. It does best in full sun, becoming leggy and thin in part shade. It's extremely drought resistant and will succumb to root rot if not planted in a well- drained, seldom-irrigated location. In the wild, it will grow in certain riparian conditions, particularly in desert regions along streams, washes, and channels that are ephemeral, drying up between rains. Deciduous in winter, desert willows may shed some leaves in extreme summers, to help conserve energy and food.

Since true willows love moist environments, “desert willow” is an oxymoron; C. linearis is not a true willow but a relative of the catalpa tree and a member of the trumpet vine family (Bignoniaceae). Its leaves do mimic those of willows: they are long and slender with smooth margins and waxy surfaces. The wax coating enables the tree to conserve water in the hot climates it prefers. The shape of the flowers, combined with the shape of its leaves, earned the desert willow its taxonomical name: Cheilos is Greek for lips, and opsis translates from Greek as “resembles.” The bright two-toned flowers (purple, lavender or pink, with white) have the tubular, droopy bottom lip shape characteristic of trumpet vine blossoms.

Once done blooming, the abundant and striking flowers develop into slender fruits six to ten inches long, many of which cling to the branches through winter into the following spring to then produce seeds with winged hairs. One source notes that fallen pods can become a landscape nuisance.

There are many common names for this lovely tree: flowering willow, desert catalpa, willow-leaved catalpa, willowleaf catalpa, bow willow, flor de mimbre, and mimbre. Mimbre is a Spanish word that is sometimes translated as willow or wicker, but technically means the twigs and sprigs of willow trees that were woven into baskets or furniture.

The desert willow is native to the Southwestern U.S. and Northern Mexico; its native range in California is restricted to the arid southern portions of our state, primarily San Bernardino and Riverside counties. The US Department of Agriculture notes that it can occur naturally as far east as southwest Kansas and eastern Oklahoma. Anywhere that's hot, sunny, and dry, and not above 5,000 feet in elevation will support this hardy tree with a life span of between 40 and 150 years.

Native peoples derived medicine, food, clothing, basketry, and shelter from desert willow trees. As a pharmaceutical, the flowers, leaves, and bark were heated and pounded to make poultices and were also steeped to make a soothing tea for coughs. Tea from the flowers contains anti-oxidants for cardiovascular health and can regulate the metabolism of glucose. Flowers were also used as a prophylactic against yeast and fungal infections, and to help heal scratches and scrapes. Flowers did double duty as food, and seed pods were also eaten. But the real heavy lifting was done by the bark and branches of this multi-purpose tree. Bark was turned into fabric for clothing and cordage for nets. Once stripped of the bark, branches became the foundational coil for baskets. Mature wood was used to frame structures and granaries, as posts for fencing, and carved into bows for hunting. And although its thin leaves don't make the desert willow what one could call a shade tree, that commodity is in such short supply in deserts that travelers would rest under what shade it did offer.

The desert willow planted at the Master Gardener Demonstration Garden does provide a little bit of shade to the succulents planted beneath it, but its real value lies in the rich blue-green of its leaves and the eye-catching color and shape of its sweet-smelling flowers. Where it occurs in nature, it creates the feeling of a small oasis in the middle of dry desert washes. As a landscape specimen, it adds a lush look during summer heat to the native, drought resistant garden. It's a winning choice for a specimen tree.

The UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu (preferred) or call (530) 538-7201.