Baccharis salicifolia – Mule-fat

Baccharis salicifolia - Mule-fat, Mule's Fat, Seep-willow, Seepwillow (flowers with a Queen (Danaus gilippus) butterfly)

Baccharis salicifolia - Mule-fat, Mule's Fat, Seep-willow, Seepwillow

Plant Name

Scientific Name: Baccharis salicifolia

Synonyms: Baccharis viminea, B. glutinosa

Common Names: Mule-fat, Mule's Fat, Seep-willow, Seepwillow

Plant Characteristics

Duration: Perennial, Evergreen

Growth Habit: Shrub

Arizona Native Status: Native

Habitat: Riparian. It grows in desert or upland washes and streams and is usually found in wetlands (~ 67%-99% of the time).

Flower Color: Creamy white disks

Flowering Season: Spring, Summer, Fall

Height: To 10 feet (3 m) tall, but usually less

Description: These plants are dioecious and have rayless flowers. The seeds are fluffy with a feathery, white pappus. The leaves are sticky, dark green, lanceolate in shape, variably toothed, and up to 6 inches (15 cm) long. Despite some of its common names, this plant is not a true willow, but it does somewhat resemble one.

Special Characteristics

Allergenic – The pollen is possibly an allergen.

Butterfly Plant – The flowers attract butterflies, especially Queen (Danaus gilippus) butterflies. This plant is a good addition to butterfly gardens (if you are not allergic to it), and plants may be available from native plant nurseries.


Kingdom: Plantae – Plants
Subkingdom: Tracheobionta – Vascular plants
Superdivision: Spermatophyta – Seed plants
Division: Magnoliophyta – Flowering plants
Class: Magnoliopsida – Dicotyledons
Subclass: Asteridae
Order: Asterales
Family: Asteraceae – Aster family
Genus: Baccharis L. – baccharis
Species: Baccharis salicifolia (Ruiz & Pav.) Pers. – mule-fat

More About This Plant

Arizona County Distribution Map