Calylophus berlandieri (Sundrops, Texas Primrose)

Plant Profile

Calylophus berlandieri, commonly known as Sundrops or Texas Primrose, is a low, spreading perennial native to the south-central US and Mexico. It features narrow, green leaves and produces a profusion of bright yellow, four-petaled, cup-shaped flowers from late spring through summer, often opening in the evening and lasting into the next day. It has a long bloom season and high heat tolerance.

Key Characteristics

• Family: Onagraceae (on-uh-GRAY-see-ee)
• Genus: Calylophus (kal-ee-LOW-fus)
• Species: berlandieri (bur-lan-dee-ER-ee)
• Synonyms: Calylophus berlandieri subsp. berlandieri, Calylophus drummondianus subsp. berlandieri

Growing Conditions

Full sun, well-drained soil. Excellent heat and drought tolerance. Hardy in USDA zones 5–9. Prefers neutral to alkaline soil.

Landscape Uses

Great for rock gardens, xeric landscapes, borders, and containers. Long bloom season provides continuous color. Attracts bees and butterflies.

Maintenance

Shear back after main flush to encourage rebloom. Divide in spring if clumps become woody. Very low maintenance.