CC Goldfields

A Golden Surprise Blooms Along Highway 4

Nestled beside the bustling Highway 4, a surprising haven exists for a rare wildflower. Here, amidst the vernal pools, flourishes the Contra Costa goldfield (Lasthenia conjugens), a dazzling display of golden blooms gracing the landscape each spring. JMLT is proud to steward the last-known stand of this endangered species within Contra Costa County. These vibrant annuals, part of the aster family, reach heights of 4 to 12 inches and boast light green, feathery leaves. Sadly, only 13 populations are known to exist across four counties in California.

From Abundance to Endangered

CC Goldfields erupting in a blanket of yellow in early Spring

The Contra Costa goldfields once thrived throughout coastal and inland areas of the state. However, development and the invasion of non-native grasses pushed this wildflower to the brink of extinction. In 1997, the federal government designated the species as endangered.

JMLT's Role in the Goldfields' Revival

JMLT's role in the goldfields' resurgence began in 2002 with the acquisition of a 30-acre conservation easement east of Hercules. Upon taking ownership, the number of plants had dwindled dramatically. Interestingly, the introduction of cattle grazing proved to be a key factor in the goldfields' recovery. Cattle grazing helped suppress the invasive grasses, creating space for the native wildflowers to flourish.

CC Goldfields: Hooray for hooves!

When JMLT took over the CC Goldfields property two decades ago, the number of plants had plummeted to nearly zero. To prosper, the flower needs vernal pools—little pools of water that form in the winter but dry out in the spring. Interestingly, the churn and divots from cattle hooves create perfect little pools. We used cattle grazing to beat back the deadly grasses and give the goldfields a chance to recover—and it worked! They’re thriving now.

This spring, we introduced 10 yearling heifers to compete with faster-growing grasses alongside the 10 bulls that graze in the fall. The extra munching is working!

A Rich Ecosystem Beyond the Goldfields

JMLT's conservation efforts extend beyond the goldfields themselves. The preserve encompasses nearby vernal pools and a section of Rodeo Creek, a rich habitat teeming with native life. Fish, amphibians like the threatened California red-legged frog, and a variety of birds, including mallards, great egrets, and belted kingfishers, all call this diverse ecosystem home. Small mammals like coyotes, raccoons, and rodents also find refuge here. JMLT conducts annual biological assessments to monitor the health of the goldfields population.

Saving the Contra Costa Goldfields: A Collaborative Effort

JMLT is proud to partner with the UC Berkeley Botanical Garden to propagate and collect seeds of the endangered Contra Costa Goldfields (Lasthenia conjugens) at our preserve. This collaboration also involves the University of Colorado at Boulder, ensuring the lineage is preserved in their seed bank for future studies on population dispersal.

The UC Botanical Garden, under the leadership of Curator Holly Forbes, played a critical role. Their team of expert horticulturalists helped with planting seeds and plugs (grown in their greenhouse since November) within the preserve. These efforts involved multiple plantings to optimize success.

UC Berkeley Botanical Garden's horticulturalists helped with planting seeds and plugs (grown in their greenhouse since November) within the preserve.

Witnessing the Golden Spectacle

For a breathtaking display of these golden gems, spring is the prime time for a visit. JMLT leads wildflower hikes during this season, offering a unique opportunity to witness an ecological success story firsthand. See our calendar of events for more information!