Rosilla
Helenium puberulum
Care
full sun
moderate
Fast, Medium, Standing; Prefers sand but tolerates garden soil.
5–5ft tall
Jun-Aug
Prized
Interior valleys and foothills from Kern County to Stanislaus County, 500-2000 ft elevation in grasslands and scrub.
Care Guide
Planting
Plant rosilla in full sun with fast to medium drainage soil - it naturally grows in streamsides and marshes, so while it tolerates regular garden soil, it prefers sandy conditions. Space plants to accommodate their variable size, as they can range from low and bushy to spindly stems nearly 5 feet tall. Plant in spring to establish before the summer blooming season (June-August), and choose a location where the soil can stay consistently moist, mimicking its native riparian habitat.
After Planting
Water regularly through your first summer to keep soil moist while the plant establishes; rosilla thrives in wet habitats and won't appreciate going bone-dry. Once established, maintain consistent moisture during the growing season rather than letting it dry out between waterings. The #1 mistake is treating it like a drought-tolerant native - this plant wants damp soil, not xeric conditions, so don't skimp on water if you want it to thrive.
Endangered & Threatened Species Supported
California Endangered Species Act listed
Wildlife Supported
Insects
larvae feed on foliage; multiple generations May-September
adults feed on nectar; provision larvae with insects
herbivorous feeding on available foliage; nymphs and adults active summer-fall
larvae utilize foliage; extended flight season March-November in California
adults and larvae feed on foliage during growing season