Adenostoma fasciculatum

white bush plant
Santa Helena trailhead | April 2016

Chamise “forms a large part of the chaparral of our mountain slopes, and when not in bloom
gives to them much the aspect imparted to the Scottish Highlands by the heather”399

Chamise (or greasewood, Adenostoma fasciculatum) is the dominant species in chaparral, which in turn is the dominant vegetation in California. Like many chaparral species, chamise has small leathery leaves that resist water loss, making it very drought tolerant, and an enlarged, woody area at the base of the stems – a burl – that stores water and energy and facilitates rapid resprouting after a wildfire.

Some people enjoy chamise for the soft olive texture it brings to our hillsides and for the creatures it shelters. Others fear it for its flammability. Chamise has a tenuous relationship with humans.

Other Common Names:


Description 4,5,11,26,27,59

Chamise is a native evergreen shrub, usually less than 12 feet (4 m) tall and densely branched with small, stiff branches. Several stems arise from a wooden mass or burl just below the soil surface. Older trunks develop grayish peeling bark. Younger stems are often reddish and may be smooth or covered with short, fine hairs. As the plant ages, dead wood accumulates. The small, resinous, evergreen leaves are needle-like, less than 1/2 inch (1.3 cm) long, in clusters that alternate along the stems. Leaves are olive green, more-or-less obovate, straight or curved. Leaf tips are smoothly rounded to obtuse or acute, and they often end with a tiny, hard point. The foliage resembles that of rosemary (Rosmarinus officinalis) or California buckwheat (Eriogonum fasciculatum).

Tiny flowers are densely packed into elongated clusters along branch ends. Flowers are radially symmetrical, bisexual, less than 7/32 inches (0.5 cm) across; clusters may be up to 5 inches (12 cm) long. There are five triangular sepals and and five, occasionally four, rounded petals. There are usually 10 or 15 stamens in five groups extending beyond the petals; anthers and pollen are light yellow. The single pistil has a superior ovary with one style and a somewhat lobed stigma, tinged with orange. The main flower period is April into July.1

The dried flower surrounds the developing fruit, persisting to maturity and tipping the stem ends with shades of bronze and brown. The fruit is an achene with one or two tiny seeds.

dried out tree branches and trunk

Older trunk with grey peeling bark | Santa Florencia overlook | July 2018

tiny green tubes on a branch

Resinous, needle-like leaves | Santa Florencia overlook | May 2011

tiny white flowers bunched on a branch

Tiny flowers in dense clusters | Photo credit: Barbara Wallach | April 2010

Distribution 5,7,27,59,89,174

Chamise is native to California and northern Baja California below about 6000 feet (2000 m). It is the most abundant species in the widespread California chaparral, often occurring in single-species stands, especially on south-facing slopes. It occurs throughout the range of chaparral – in foothills and mountains from the California-Oregon border into Baja, California.

In the Reserve, chamise is restricted to the band of “mixed chaparral” that occurs on the upper slopes above the sage scrub and below the houses. In mixed chaparral, chamise is one of several drought-tolerant evergreen shrubs, including wart-stemmed ceanothus (Ceanothus verrucosis), lemonade berry (Rhus integrefolia) and mission manzanita (Xylococcus bicolor). Except when blooming, individuals blend into the tapestry of chaparral species. Chamise is rarely found in the sage scrub below. It can best be viewed closely from the higher spots such as Santa Florencia overlook, the top of Annie’s Canyon and the Solana Hills access road (temporarily closed during the I-5 widening).

Classification 2,11,27

Chamise is a dicot angiosperm in the rose family, Rosaceae. This is a variable family.44 Plants generally have bisexual flowers that are radially symmetrical with five petals and five to numerous, spirally arranged stamens.

The rose family includes many commercial plants including fruits such as plums, peaches, apples and strawberries, and ornamentals such as roses and pyracantha. Of the nine species in the rose family in the Reserve,48 the most frequently encountered is toyon (Heteromeles arbutifolia).

Chamise is one of two species within the genus Adenostoma2,306 and the only one in the Reserve.48 Three varieties of chamise are currently accepted, distinguished on the basis of plant height, and leaf size and shape. I have examined only a few individuals and they fell in the range of overlap between var. fasciculatum and var. obtusifolium, tending toward the latter, but I have not had enough experience with this species to hazard a determination.

Jepson eFlora Taxon Page
Small white flowers

Santa Florencia overlook | April 2016

close up of white flower pods clumped together

Santa Florencia overlook | May 2011

white flowers and green bushes overlooking the east basin

Santa Florencia overlook | April 2016


Chamise is the quintessential chaparral species.It dominate much of that vegetation type, where its numerous short branches interweave with those of neighboring plants forming the impenetrable thicket that chaparral is known for. It also has most of the characteristics that adapt chaparral species to lack of summer rain and to periodic fires.27,174 The leaves are small, thick and waxy, slowing water loss. The root system is extensive.5,38 Their radial extent is generally twice that of the crown while the main roots have been excavated to 25 feet (8 m) depth before disappearing. Thus, chamise has efficient uptake of rain water as well as access to subsurface water sources.

Chamise stems arise from a large, subsurface, woody mass – a burl – which is protected from fire by the surrounding soil. The burl contains tissues capable of generating new growth, providing rapid regeneration after a fire.5 Chamise also produces two types of seed; a few are capable of germination the following season, but many need heat or chemical cues from fire to sprout. These build up a seed bank below the soil surface, providing new plants after a fire. Curiously, chamise is the only chaparral shrub with both strategies.5,36 Neither strategy however, assures fire survival, which depends upon season, fire intensity and time since last burn.5

Ironically, chamise also has characteristics that seem to promote fire, such as small, resinous leaves that are highly flammable during the dry season (hence the common name greasewood),26 and quantities of small, dead branches and dried flowers that accumulate in the canopy providing ready fuel.426 These would seem to be undesirable characteristics if burning is disadvantageous to chamise. The unanswered question is the extent to which these may be considered adaptations to promote fires, at least fires of the proper frequency and intensity to maximize the survival of chamise. The possibility that flammability is an ecological and evolutionary driving mechanism (like flower color and shape or drought tolerance) is currently receiving attention from ecologists.426

dried out orange and white tiny flowers on branches in a bush

Santa Florencia overlook | May 2017

green bush

Santa Florencia overlook | July 2018

microscopic view of tiny green tubes on branch

Santa Florencia overlook | July 2018

Human Uses

Native Americans used chamise medicinally, often as a wash for various ailments,282 and they used the hard wood as firewood, for construction and for tools.282 To make flutes, the Chumash hollowed out the pithy core of small branches of elderberry (Sambucus nigra) with a drill or awl of chamise.15 Chumash, Luisaño and Kumeyaay made arrow foreshafts or arrow points from chamise. For foreshafts, green wood was dried in a groove of heated soapstone which straightened and hardened the wood. Kumeyaay made arrow points by heating chamise points carefully over coals until they got “hard as iron”.272

microscopic view of tiny white flowers

Stamens grouped in clusters | Santa Florencia overlook | May 2017

close up of branch with tiny green tubes

Santa Florencia overlook | April 2016

bush with white flowers throughout

Santa Florencia overlook | April 2016

Interesting Facts

The name chamise comes from the Latin word “chamiso” and the Portuguese or Galican word “chamica,” meaning dry brush or firewood.23,27 Thickets of chamise are sometimes called chamissal.41

The vegetation type, chaparral, is named after a similar scrubby dense vegetation type in Spain, “chaparro.”36,41 Our word chaps – the thick leathery leg protectors that horsemen wear – comes from the same Spanish root.

close up of tiny white flowers in a bush

Santa Florencia overlook | April 2016

field of white flower bushes

The same hills, in the Summer | Santa Florencia overlook | July 2018

white flower bushes in a field

Spring in the hills | Santa Florencia overlook | April 2016

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