Dense Spike-primrose
Epilobium densiflorum
Care
0–3ft tall
Friendly
Prized
Inner Coast Ranges and Sierra Nevada foothills from Fresno County north to Butte County, 1000-4000 ft elevation in chaparral and open woodlands.
Care Guide
Planting
Plant Dense Spike-primrose in spring or fall when temperatures are mild. This native annual thrives in full sun and adapts to a range of habitats - from valley grasslands to mountain forests - so it's flexible about location in the Bay Area. Space plants about 12 inches apart to allow room for growth, as this species can reach over 3 feet tall. While specific soil requirements aren't detailed, choose a spot with good drainage since this plant naturally occurs across diverse California elevations and plant communities.
After Planting
Water regularly during the first growing season to help the plant establish, then reduce watering as it matures since it's adapted to California's dry summers. As an annual, Dense Spike-primrose completes its lifecycle in one year, so expect it to flower densely along its upper stems before setting seed in late summer. The main mistake is overwatering once established - this native plant is built for the Bay Area's drier months and doesn't need supplemental irrigation once its root system develops. Deadhead spent flowers if you want to extend blooming, or let it self-seed for volunteers next year.
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Wildlife Supported
Insects
Host plant for larvae; multiple broods spring through fall
Critical summer foraging resource during colony growth and reproduction
Primary foraging period during peak flowering
Early to mid-summer foraging