Orcutt’s Goldenbush

Hazardia orcuttii

single Orcutt's Goldenbush with yellow blooms

Orcutt’s goldenbush is a small, evergreen shrub that blooms yellow in the late summer and early fall. It resembles goldenbush (Isocoma menziesii) and sawtooth goldenbush (Hazardia squarrosa). One difference is the flower head. Orcutt’s goldenbush has both disk and ray flowers (like a daisy), while the other two have only disk flowers.

A few years ago, Orcutt’s goldenbush existed in California as a single small population in Manchester Habitat Conservation Area, just north of San Elijo Lagoon. To reduce the risk of losing this population to fire or disease, seeds were collected, grown in a local nursery and the seedlings planted in nearby protected areas. Stonebridge Mesa, on the east end of the Reserve, received 156 seedlings. In 2012 only 46 plants survived, but many were blooming, and seedlings were found – happy signs of recruitment. We remain optimistic that the new population will survive.

Other Common Names:

Orcutt's hazardia, Orcutt's bristleweed

Description 2

Orcutt’s goldenbush is a small, rounded, evergreen  shrub, usually three feet (1 m) or less in height. Branches are reddish. Green leaves have a tinge of olive color and both surfaces are resinous, giving them a lustrous sheen; the color and luster makes the plant easy to recognize from a distance. Leaves are 3/4 – 2 inches long (2 – 5 cm), obovate, with a sharp tip and smooth margins.

The yellow flowers are composite heads of two types of florets. There are 8-12 ray florets surrounding 10-20 disk florets. These compound flower heads are born in terminal and auxiliary clusters. Ray florets are female, with a two-branched pistil. Disk florets are bisexual with five stamens in a column around the pistil. Below each compound flower are numerous overlapping green, resinous phyllaries that are curved back at the tips. Flowers bloom primarily from June into October.1

Seeds are about 1/8 inch long (3 – 4.5 mm), slim, each with a tawny pappus which disperses the seed in the wind. Dried petals often remain among the developing seeds, giving the seed head an old, unkempt appearance; it doesn’t invite wishing as a dandelion puff does.

Long almond shaped leaves grow upward in stems
yellow flowers among green pine cone-like buds
dried flowers ready to release seeds

Distribution

The natural range of Orcutt’s goldenbush is a narrow coastal strip from Encinitas, CA into northern Baja California, below 300 feet (100 m), generally associated with coastal sage scrub and maritime chaparral7,45 and often with soils with a relatively high proportion of clay.45,113

As of this writing (2015), only one natural population of Orcutt’s hazardia has been found in the United States. This occurs in the Manchester Habitat Conservation area, about one mile (2 km) north of San Elijo Lagoon Ecological Reserve.113,187 Additionally, the species has been planted in four local protected areas,187 and in San Diego Botanic Garden.188 The species is known from only nine locations in Baja.187 Orcutt’s goldenbush has been classified as seriously endangered by the California Native Plant Society45 and has recently been listed as endangered under Mexican environmental law.187

In the Reserve, Orcutt’s hazardia grows on Stonebridge Mesa, one of the out-planted populations.187

Orcutt's Goldenbush informational trail sign

Classification

Orcutt’s goldenbush is a dicot angiosperm in the sunflower family, the Asteraceae.2 This is the largest family of vascular plants in the Northern Hemisphere.143 “Flowers” of Asteraceae are made up of one or both of two types of flowers (florets): symmetrical disk florets and strapped-shaped ray florets. These are crowded onto a common base (receptacle), and together are often assumed to be a single flower, which we call a flower head.11,44,49

Other Asteraceae that commonly occur in the Reserve include bush sunflower (Encelia californica) and California sagebrush (Artemisia californica).

The genus Hazardia was formerly included within the large genus Haplopappus.189 There is one other species of Hazardia, sawtooth goldenbush (H. squarossa) has been found in the Reserve.48 The closely related goldenbush (Isocoma menziesii) is very common.

Jepson eFlora Taxon Page
Close up of Orcutt's Goldenbush blooms
yellow disk flower with pappus showing anthers
seed with pappas under microscope

Ecology

Little is known about the ecology, or general biology of Orcutt’s goldenbush.113

The very small size and restricted distribution of the single wild population in the United States makes it extremely vulnerable to any disturbance, although the success of the out-planted populations in nearby areas mitigates this somewhat. A newly recognized threat is the possibility that Orcutt’s goldenbush will lose its genetic identity because of hybridization with the related sawtooth goldenbush (H. squarossa).187

Budding and blooming Orcutt's Goldenbush blossoms
looking into small yellow blossom
mosquito resting on single yellow blossom

Human Uses

We have found no information about uses of Orcutt’s goldenbush.

single yellow blossom surrounded by spikes green buds
yellow flower blooming among green spikes buds
long almond shaped resinous leaf under microscope

Interesting Facts

The only wild population of Orcutt’s goldenbush in the U.S. was a “vigorous population” discovered in Encinitas, CA in 1979, on land already approved for housing.190 Some plants were transplanted out of the proposed housing area; a population was established at Quail Gardens (now San Diego Botanic Garden).188 Subsequent development in the original area reduced the remaining population by about half. The population in 2012 was about 670 plants in an area less than five acres,113, 187 located within the protected Manchester Habitat Conservation Area. To guard against the loss of the entire population from a local catastrophe (especially wildfire), four additional, “experimental” populations were established in nearby protected areas from seeds of the wild plants. A second site was established in Manchester Habitat Conservation Area, and two sites in Carlsbad (Kelly Ranch and Rancho La Costa Habitat Conservation Area). The fourth population is on the Stonebridge Mesa area of San Elijo Lagoon Ecological Reserve.

One hundred and fifty-six plants were established on Stonebridge Mesa.187 By 2005, high initial mortality had reduced the population to 75 plants. In 2012 only 46 adults were found, but there were 18 seedlings. Although less than a third of the original plants have survived, many of these were – and still, are in 2015 – healthy and blooming. Hopefully, the presence of seedlings indicates the potential for long-term population reproduction and survival.

the only remaining wild population of Orcutt's Goldenbushes at the Manchester Habitat Conservation area
single Orcutt's Goldenbush growing in dry brush
several small Orcutt's Goldenbushes growing on trail side

Photo Gallery