Oenothera elata
tall evening primrose
Overview
Oenothera elata is a biennial or short-lived perennial in the evening primrose family, forming a basal rosette in its first year and a stout, often reddish flowering stalk 3-8 feet (0.9-2.4 m) tall in its second. The lance-shaped leaves are 4-12 inches (10-30 cm) long, hairy, and crowded at the base, becoming smaller up the stem. Yellow four-petaled flowers, 2-3.5 inches (5-9 cm) across, open quickly in the evening, release a sweet scent, and age to orange or reddish by the next afternoon. Because the flowers open at dusk, they are worked mainly by hawk moths and other night pollinators. Bloom runs through summer, with new flowers opening over many weeks up the lengthening spike. Native to moist meadows, streambanks, and disturbed ground across the western United States and into Mexico, it grows most strongly where the soil stays damp through the growing season. After flowering and setting its many small seeds the plant usually dies, relying on self-sown seedlings to continue. The tall stems can flop in rich soil or wind and the rosettes take a full year before they bloom, so the plant reads as short-lived rather than permanent.
Native Range
Oenothera elata is native to the western United States and Mexico, from the Pacific states east to the Rocky Mountains. It grows in moist meadows, along streams and ditches, and in damp disturbed ground from low elevations into the mountains.Suggested Uses
Oenothera elata is used in native and pollinator gardens, moist meadows, rain gardens, and streamside plantings. Its evening flowers draw hawk moths and other night-flying pollinators.How to Identify
Appearance
Size & Dimensions
Height3' - 8'
Width/Spread1' - 2'
Bloom Information
Flowering extends from June to September in most of its range. Individual flowers open near dusk, last about one day, and turn orange to red as they wilt, while new buds open in succession up the stem. A single plant can flower for two months or more.
Detailed Descriptions
Flower Description
yellow, aging orange-redFoliage Description
greenGrowing Conditions
Sun Requirements
Requires 6-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grow Oenothera elata in full sun in moist to average soil with a pH near 6.0 to 7.5. It tolerates a range of soils but flowers most freely where moisture is steady, and it withstands seasonal flooding better than drought. Sow seed in fall or spring; first-year plants form only a rosette and bloom the following summer. Rich soil and shade produce taller, weaker stems that may need staking or a sheltered spot. Letting some seed ripen keeps the planting going, since most plants die after flowering.Pruning
Remove spent flower spikes after bloom to limit self-seeding, or leave them to drop seed for the next generation. Cut declining second-year plants to the ground once flowering ends. No other pruning is required.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
fall
✓ Toxicity
Non-toxicPlanting Guide
Planting Methods & Timing
Planting Method
direct sow
Direct Sow Timing
fall or early spring
Plant Spacing
18 inches