North America Native Plant

Hartweg’s Sundrops

Botanical name: Calylophus hartwegii fendleri

USDA symbol: CAHAF

Life cycle: perennial

Habit: subshrub

Native status: Native to the lower 48 states  

Synonyms: Oenothera fendleri A. Gray (OEFE)  âš˜  Oenothera hartwegii Benth. var. fendleri (A. Gray) A. Gray (OEHAF3)   

Hartweg’s Sundrops: A Cheerful Native Wildflower for Low-Maintenance Gardens Looking for a sunny, low-maintenance addition to your native plant garden? Meet Hartweg’s sundrops (Calylophus hartwegii fendleri), a delightful perennial wildflower that brings months of bright yellow blooms to drought-tolerant landscapes. This charming native herb might just be the cheerful ground ...

Hartweg’s Sundrops: A Cheerful Native Wildflower for Low-Maintenance Gardens

Looking for a sunny, low-maintenance addition to your native plant garden? Meet Hartweg’s sundrops (Calylophus hartwegii fendleri), a delightful perennial wildflower that brings months of bright yellow blooms to drought-tolerant landscapes. This charming native herb might just be the cheerful ground cover you’ve been searching for!

What Are Hartweg’s Sundrops?

Hartweg’s sundrops is a native perennial forb that belongs to the evening primrose family. Unlike its woody shrub cousins, this herbaceous plant stays close to the ground and comes back year after year from its root system. You might also see it listed under its botanical synonyms Oenothera fendleri or Oenothera hartwegii var. fendleri in older gardening references.

This native beauty calls the American Southwest home, naturally occurring across Arizona, Colorado, Kansas, New Mexico, Oklahoma, and Texas. It’s perfectly adapted to the challenging growing conditions of these regions, making it an excellent choice for gardeners in these states who want to work with nature rather than against it.

Why Grow Hartweg’s Sundrops?

There are plenty of reasons to fall in love with this sunny native:

  • Long blooming season: Bright yellow, four-petaled flowers appear from spring through fall
  • Drought tolerant: Once established, it thrives with minimal water
  • Pollinator magnet: Bees, butterflies, and other beneficial insects love the flowers
  • Low maintenance: Perfect for gardeners who want beauty without the fuss
  • Native plant benefits: Supports local ecosystems and wildlife

Perfect Garden Roles

Hartweg’s sundrops shines in several landscape settings:

  • Rock gardens: Its low-growing habit makes it ideal for tucking between stones
  • Xeriscaping: A natural choice for water-wise landscaping
  • Native plant gardens: Fits beautifully with other southwestern natives
  • Prairie restorations: Helps recreate natural grassland communities
  • Ground cover: Provides colorful coverage in sunny, dry areas

Growing Hartweg’s Sundrops Successfully

The best part about growing this native gem? It’s refreshingly easy! Here’s what you need to know:

Location and Soil

Plant Hartweg’s sundrops in full sun locations with well-draining soil. This plant absolutely cannot tolerate wet feet, so avoid low-lying areas where water might collect. Sandy or rocky soils that would challenge other plants are perfect for this drought-adapted native.

Hardiness

This tough perennial thrives in USDA hardiness zones 5-9, making it suitable for a wide range of climates from the northern plains down to the hot Southwest.

Planting and Care Tips

  • Watering: Water regularly the first growing season to establish roots, then reduce to occasional deep watering
  • Fertilizing: Skip the fertilizer – this native prefers lean soils
  • Maintenance: Minimal pruning needed; may self-seed in favorable conditions
  • Spacing: Allow room for the plant to spread as ground cover

Supporting Your Local Ecosystem

By choosing Hartweg’s sundrops, you’re doing more than just adding pretty flowers to your garden. Native plants like this one support local pollinator populations and contribute to healthy, sustainable landscapes. The bright yellow blooms provide nectar for native bees and butterflies, while the plant itself fits naturally into regional ecosystems.

Is Hartweg’s Sundrops Right for Your Garden?

This native wildflower is an excellent choice if you:

  • Live in its native range (Southwest and south-central United States)
  • Want a low-maintenance, drought-tolerant plant
  • Love supporting native pollinators
  • Enjoy long-blooming flowers
  • Need ground cover for sunny, dry spots

However, you might want to look elsewhere if you have consistently moist soil or heavily shaded areas, as this sun-loving native won’t thrive in those conditions.

Hartweg’s sundrops proves that native doesn’t mean boring – sometimes it means discovering a cheerful, easy-care plant that’s been thriving in your region long before any of us started gardening. Give this sunny native a try, and you might just find yourself with a new favorite wildflower!

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