Arroyo Willow (Salix lasiolepis) is an abundant and widespread native small tree or shrub that grows in northern, southern and central California. Arroyo Willow likes water and in the garden must have constantly moist soil. It is a fast-growing small tree, reaching 15 to 30 feet high and 5 to 10 feet wide. The leaves are long and thin. Being deciduous, Arroyo Willow is leafless part of the year. The flower is a yellowish catkin that becomes a fluffy white mass of seeds.

Willows (Salix spp.) are very important wildlife plants, used by birds, insects, amphibians and mammals. Numerous insects, especially wasps, lay their eggs on willow leaves, forming galls. These galls are usually not harmful to the plant and should not be viewed as pests.

Arroyo Willow grows in full sun in a variety of soils, as long as it has adequate drainage. It is recommended as erosion control near streams. Spreading by root runners it can be invasive in moist areas. Gardeners with a bog or pond use it with other wetland plants such as Maple, Spicebush, Dogwood, Currant, and California Wildrose. It can be pruned or sheared in winter to form a hedge.