
Photo: Bureau of Land Management, US Department of the InteriorPublic domainvia Wikimedia Commons
Contra Costa goldfields Plant Care
Lasthenia conjugens Greene
Updated · Sources · How we source care data
Lasthenia conjugens, commonly known as Contra Costa goldfields, is an endangered species of wildflower endemic to a limited range within the San Francisco Bay Area of the state of California, USA. Specifically this rare species occurs in Napa, Santa Barbara, Solano, Contra Costa, Santa Clara, Monterey and Alameda Counties. This annual herb typically flowers from March through June, and its colonies grow in vernal pool habitats at elevations not exceeding 100 meters above sea level. The Jepson Manual notes that the present distribution is limited to the deltaic Sacramento Valley, principally Napa and Solano Counties, but the historic range of L. conjugens is known to be significantly wider. In any case, historically the range has included parts of the North Coast, Sacramento Valley, and San Francisco Bay Area as well as the South Coast. Alternatively and less frequently this taxon has been referred to as Baeria fremontii var. conjugens.
Every 3–5 days
Full sun to partial shade
50–80°F
40–60%
At a glance
How do you care for Contra Costa goldfields?
Plant Contra Costa goldfields in full sun to partial shade (USDA zones 12a) and water a young shrub every 3–5 days until it is established. It tolerates temperatures of 50–80°F (10–27°C). Fertilize it every 6 months during the growing season.
Where Is the Contra Costa goldfields Native To?
What Is the Contra Costa goldfields?
Contra Costa goldfields (Lasthenia conjugens) belongs to the Asteraceae family within the Lasthenia genus. Contra Costa goldfields is native to a limited range within the San Francisco Bay Area of the state of California, USA. Contra Costa goldfields is also known as Baeria fremontii.
Contra Costa goldfields displays a low rosette, spreading ground cover growth habit, reaching up to 0.5 ft tall with a spread of approximately 1 ft. Contra Costa goldfields produces small daisy-like yellow flowers in clusters.
Leaf size: approximately 1 inches.
How Often Should You Water a Contra Costa goldfields?
Water a young or newly planted Contra Costa goldfields every 3–5 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established shrubs mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.
Watering Frequency
Every 3–5 days
Until established; then in dry spells
What Light Does the Contra Costa goldfields Need?
Contra Costa goldfields thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the Contra Costa goldfields Prefer?
Lasthenia conjugens tolerates temperatures of 50–80°F. Contra Costa goldfields prefers humidity levels of 40–60%.
Temperature
50–80°F
Humidity
40–60%
What Soil Mix Works Best for a Contra Costa goldfields?
Well-draining sandy soil mix with some organic matter. Good drainage is essential for Contra Costa goldfields to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Contra Costa goldfields?
Feed Contra Costa goldfields every 6 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established shrubs in good soil often need little extra feeding, so let weak growth or pale foliage guide you.
Stop feeding by late summer so new growth can harden before winter.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
Where Should You Plant a Contra Costa goldfields?
Choose a spot with full sun to partial shade and well-draining sandy soil mix with some organic matter. Avoid low spots where water collects after rain.
Contra Costa goldfields is suited to USDA Zone 12a.
Plant container-grown or balled-and-burlapped shrubs in spring or early autumn, setting the root flare at soil level, and water well after planting.
How Far Apart Should You Plant a Contra Costa goldfields?
Contra Costa goldfields can spread to about 1 ft (0.3 m) and reach about 1 ft (0 m) tall. Space plants about 1 ft (0.3 m) apart so mature crowns don't crowd each other, and plant at least half that distance from buildings, fences and paths.
Planning a row or hedge? Try the plant spacing calculator.
How Do You Prune a Contra Costa goldfields?
Prune Contra Costa goldfields while it is dormant in late winter: first remove dead, damaged and crossing branches, then thin lightly for shape.
If it flowers in spring, prune right after flowering instead so you don't remove next year's buds. Never take off more than about a quarter of the shrub in one year.
How Do You Care for a Contra Costa goldfields in Winter?
Contra Costa goldfields is frost-tender (hardy to USDA zone 12). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.
How Do You Propagate a Contra Costa goldfields?
Contra Costa goldfields can be propagated through seeds, division of clumps. Similar propagation techniques also apply to burke's goldfields plant care, which shares the same genus.
Is the Contra Costa goldfields Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Contra Costa goldfields, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Contra Costa goldfields?
Contra Costa goldfields is susceptible to aphids, spider mites, whiteflies. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the Contra Costa goldfields Need?
Contra Costa goldfields grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Contra Costa goldfields is native to a limited range within the San Francisco Bay Area of the state of California, USA. In cooler regions, grow Contra Costa goldfields as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Contra Costa goldfields is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Lasthenia genus — compare its care with other Lasthenia species on PlantoScan.
Lasthenia is part of the Asteraceae plant family — browse all Asteraceae genera and species.
Contra Costa goldfields thrives in bright light and direct sun — see other bright-light plants.
More Lasthenia Species
Other Lasthenia species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Lasthenia conjugens Greene, family Asteraceae (first published in Pittonia 1(5): 221 (1888)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Contra Costa goldfields, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Photo: Bureau of Land Management, US Department of the Interior, Public domain, Wikimedia Commons — original.
- Hardiness zone: USDA Zone 12a, calculated from the plant's minimum temperature.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
