North America Native Plant

Hartweg’s Sundrops

Botanical name: Calylophus hartwegii filifolius

USDA symbol: CAHAF2

Life cycle: perennial

Habit: subshrub

Native status: Native to the lower 48 states  

Synonyms: Calylophus hartwegii (Benth.) P.H. Raven var. filifolius (Eastw.) Shinners (CAHAF3)  âš˜  Oenothera filifolia (Eastw.) Tidestr. (OEFI)  âš˜  Oenothera hartwegii Benth. var. filifolia (Eastw.) Munz (OEHAF2)  âš˜  Oenothera tubicula A. Gray var. filifolia Eastw. (OETUF)   

Hartweg’s Sundrops: A Bright Spot for Your Native Garden Looking for a cheerful, low-maintenance native plant that can handle tough conditions? Meet Hartweg’s sundrops (Calylophus hartwegii filifolius), a delightful perennial that’s ready to brighten up your garden with minimal fuss. This southwestern beauty proves that sometimes the best things come ...

Hartweg’s Sundrops: A Bright Spot for Your Native Garden

Looking for a cheerful, low-maintenance native plant that can handle tough conditions? Meet Hartweg’s sundrops (Calylophus hartwegii filifolius), a delightful perennial that’s ready to brighten up your garden with minimal fuss. This southwestern beauty proves that sometimes the best things come in small, sunny packages.

What Makes Hartweg’s Sundrops Special?

Hartweg’s sundrops is a true native of the American Southwest, naturally occurring in Texas and New Mexico. As a perennial forb (that’s botanist-speak for a non-woody flowering plant), it returns year after year to grace your garden with its presence. You might also see it listed under various scientific synonyms, including Oenothera hartwegii var. filifolia, but don’t let the name variations confuse you – it’s all the same sunny plant!

This plant grows naturally across Texas and New Mexico, where it has adapted to thrive in challenging conditions that would make other plants wilt.

A Garden Gem That Works Hard

What sets Hartweg’s sundrops apart is its incredible versatility and resilience. This low-growing perennial produces bright yellow, four-petaled flowers that seem to glow in the landscape from spring through fall. The blooms are like little golden cups that catch and reflect sunlight, creating a cheerful display that’s hard to ignore.

The plant forms a spreading, ground-hugging habit that makes it perfect for:

  • Rock gardens and xerophytic landscapes
  • Native plant gardens
  • Drought-tolerant ground cover
  • Low-water landscaping projects

Why Pollinators (and You) Will Love It

Those bright yellow flowers aren’t just pretty faces – they’re pollinator magnets! Bees, butterflies, and other beneficial insects flock to Hartweg’s sundrops for nectar and pollen. By planting this native beauty, you’re not just adding color to your garden; you’re supporting local ecosystems and helping maintain healthy pollinator populations.

Growing Hartweg’s Sundrops Successfully

Here’s the best news: Hartweg’s sundrops is refreshingly low-maintenance. This plant thrives in USDA hardiness zones 7-10, making it suitable for much of the southern United States.

Perfect Growing Conditions

  • Sunlight: Full sun is essential – this plant loves to bask in bright light
  • Soil: Well-draining soil is crucial; it can handle poor, rocky, or sandy soils
  • Water: Drought tolerant once established – perfect for water-wise gardening
  • Climate: Adapted to hot, dry conditions typical of the Southwest

Planting and Care Tips

Getting started with Hartweg’s sundrops is straightforward. Plant in spring after the last frost, giving each plant enough space to spread. While specific spacing requirements can vary, most ground-covering plants appreciate room to establish their natural growth pattern.

Once established (usually after the first growing season), this plant is remarkably self-sufficient. Water occasionally during extreme drought, but otherwise, let nature take the lead. You might want to trim back spent flowers or tidy up the plant occasionally, but heavy maintenance isn’t necessary.

Is This Plant Right for Your Garden?

Hartweg’s sundrops shines in the right setting. Consider this plant if you:

  • Live in zones 7-10 and want a reliable native perennial
  • Need drought-tolerant plants for low-water landscaping
  • Want to support local pollinators with native flowers
  • Appreciate low-maintenance plants that deliver consistent beauty
  • Are creating rock gardens or xerophytic landscapes

However, this might not be your best choice if you have consistently moist soil, heavy shade, or live in areas with very cold winters outside its hardiness range.

A Sunny Addition to Native Gardens

Hartweg’s sundrops represents everything wonderful about native plants: beauty, resilience, ecological value, and ease of care. When you choose this southwestern native, you’re getting a plant that’s perfectly adapted to its environment, supports local wildlife, and brings months of cheerful yellow blooms to your landscape.

Whether you’re just starting your native plant journey or you’re a seasoned gardener looking for reliable performers, Hartweg’s sundrops deserves a sunny spot in your garden. After all, who couldn’t use a little more sunshine in their outdoor space?

Hartweg’s Sundrops

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Myrtales

Family

Onagraceae Juss. - Evening Primrose family

Genus

Calylophus Spach - sundrops

Species

Calylophus hartwegii (Benth.) P.H. Raven - Hartweg's sundrops

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA