Oenothera speciosa
Light: Full sun to partial shade; afternoon shade is beneficial in Phoenix’s intense summer heat.
Water: Low to moderate water once established. Water deeply, then let the upper soil dry; occasional summer irrigation helps maintain foliage during extreme heat.
Soil: Well-drained sandy or loamy soil; tolerates alkaline soil and relatively poor fertility. Avoid persistently soggy conditions.
Mature size: 8–18 inches tall and 2–3 feet wide initially; spreads farther over time to form large colonies.
Bloom: Primarily spring to early summer in Phoenix; occasional repeat blooms in fall with cooler temperatures and adequate moisture.
Evergreen / deciduous: Semi-evergreen in mild conditions; may die back during winter cold or become dormant during extreme summer heat and drought.
Growth rate: Fast.