SafePlants

Calylophus hartwegii: Hartweg's Sundrops

Discover the beauty of Calylophus hartwegii, commonly known as Hartweg's Sundrops or Western Primrose. This captivating plant, with its bright yellow, cup-shaped flowers, adds a touch of sunshine to any garden.

Considerations for Pets

• This plant's narrow leaves and small parts might be tempting for pets to nibble on, so observe your furry friends around it.

Taxonomy and Nomenclature

• Scientific Name: Calylophus hartwegii (Benth.) P.H. Raven
• Family: Onagraceae (Evening-Primrose Family)
• Common Names: Hartweg's Sundrops, Western Primrose, Fendler Evening Primrose
• Synonyms: Oenothera hartwegii
• Subspecies:
  • Calylophus hartwegii subsp. hartwegii
  • Calylophus hartwegii subsp. pubescens (A. Gray) Towner & P.H. Raven
  • Calylophus hartwegii fendleri

Distribution and Habitat

Hartweg's Sundrops is native to a range of regions:

• Kansas
• Oklahoma
• Colorado
• Arizona
• New Mexico
• Texas
• Parts of Northern Mexico

This plant thrives in hot, dry areas and tolerates a variety of soil types, including clay, sandy, and caliche soils.

Morphological Characteristics

• Calylophus hartwegii is a somewhat upright, perennial groundcover.
• It features narrow, green to gray-green foliage.
• The flowers are bright to lemon yellow, cup-shaped, and approximately 1 inch in diameter.
• Flowers open at dusk and may fade to orange as they age.
• Stems are decumbent or slightly ascending, usually branched.

Quirky Facts

• The plant's flowers are known to open at dusk, a characteristic of the Evening Primrose family.
• The flower color may change from bright yellow to orange.

Additional Information

• Hartweg's Sundrops typically blooms from June through August.