Castilleja grisea Plant Care
Castilleja grisea Dunkle
Updated · Sources · How we source care data
Castilleja grisea is a rare species of Indian paintbrush known by the common name San Clemente Island Indian paintbrush. It is endemic to San Clemente Island, one of the Channel Islands of California.
Every 7–14 days
Full sun to partial shade
50–80°F
40–60%
At a glance
How do you care for Castilleja grisea?
Plant Castilleja grisea in full sun to partial shade (USDA zones 12a) and water a young shrub every 7–14 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 Castilleja grisea Native To?
What Is the Castilleja grisea?
Castilleja grisea (Castilleja grisea) belongs to the Orobanchaceae family within the Castilleja genus. Castilleja grisea is native to San Clemente Island, one of the Channel Islands of California.
Castilleja grisea displays an upright, bushy growth habit, reaching up to 1.5 ft tall with a spread of approximately 1 ft. Castilleja grisea produces colorful bracts resembling a paintbrush.
Leaf size: approximately 4 inches.
How Often Should You Water a Castilleja grisea?
Water a young or newly planted Castilleja grisea every 7–14 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 7–14 days
Until established; then in dry spells
What Light Does the Castilleja grisea Need?
Castilleja grisea thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the Castilleja grisea Prefer?
Castilleja grisea tolerates temperatures of 50–80°F. Castilleja grisea prefers humidity levels of 40–60%.
Temperature
50–80°F
Humidity
40–60%
What Soil Mix Works Best for a Castilleja grisea?
Well-draining sandy soil with some organic matter. Good drainage is essential for Castilleja grisea to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Castilleja grisea?
Feed Castilleja grisea 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 Castilleja grisea?
Choose a spot with full sun to partial shade and well-draining sandy soil with some organic matter. Avoid low spots where water collects after rain.
Castilleja grisea 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 Castilleja grisea?
Castilleja grisea can spread to about 1 ft (0.3 m) and reach about 2 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 Castilleja grisea?
Prune Castilleja grisea 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 Castilleja grisea in Winter?
Castilleja grisea 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 Castilleja grisea?
Castilleja grisea can be propagated through seeds. Similar propagation techniques also apply to castilleja hyetophila plant care, which shares the same genus.
Is the Castilleja grisea Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Castilleja grisea, 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 Castilleja grisea?
Castilleja grisea is susceptible to aphids, whiteflies, spider mites. 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 Castilleja grisea Need?
Castilleja grisea grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Castilleja grisea is native to San Clemente Island, one of the Channel Islands of California. In cooler regions, grow Castilleja grisea as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Castilleja grisea 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 Castilleja genus — compare its care with other Castilleja species on PlantoScan.
Castilleja is part of the Orobanchaceae plant family — browse all Orobanchaceae genera and species.
Castilleja grisea thrives in bright light and direct sun — see other bright-light plants.
More Castilleja Species
Other Castilleja species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Castilleja grisea Dunkle, family Orobanchaceae (first published in Bull. S. Calif. Acad. Sci. 42: 31 (1943)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Castilleja grisea, 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.
- 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.
