Calylophus Species, Lavender-leaf Sundrops, Hartweg's Sundrops, Western Primrose

Calylophus hartwegii

Family: Onagraceae (on-uh-GRAY-see-ee) (Info)
Genus: Calylophus (kal-ee-LOW-fus) (Info)
Species: hartwegii (hart-WEG-ee-eye) (Info)
Synonym:Oenothera hartwegii
Synonym:Salpingia hartwegii



Water Requirements:

Drought-tolerant; suitable for xeriscaping

Sun Exposure:

Full Sun


Unknown - Tell us

Foliage Color:



12-18 in. (30-45 cm)


15-18 in. (38-45 cm)


USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

Where to Grow:

Unknown - Tell us



Bloom Color:

Bright Yellow

Bloom Characteristics:

Unknown - Tell us

Bloom Size:

Unknown - Tell us

Bloom Time:

Mid Summer

Late Summer/Early Fall

Blooms repeatedly

Other details:

Unknown - Tell us

Soil pH requirements:

Unknown - Tell us

Patent Information:


Propagation Methods:

By dividing the rootball

Seed Collecting:

Unknown - Tell us


This plant is said to grow outdoors in the following regions:

Hereford, Arizona

Sierra Vista, Arizona

Albuquerque, New Mexico

Arlington, Texas

Colleyville, Texas

Fort Worth, Texas

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Gardeners' Notes:


On Jan 5, 2013, shindagger from Oklahoma City, OK wrote:

I have this plant growing in both full sun and part sun here in Oklahoma. It does equally well in either situation. It will tolerate quite a lot of shade. Naturalizes well, but is not invasive. Its blooms look like a primrose but with slightly smaller flowers and they stay open in the afternoon.


On May 16, 2010, kman_blue from (Zone 6b) wrote:

Hartweg's Sundrops is native to Kansas, Oklahoma, Colorado, Arizona, New Mexico, and Texas and parts of Northern Mexico. It's not endemic to Texas as has been stated. I've seen it growing in the short grass prairies in and around Elkhart, KS growing on sandy soils in well drained short grass prairies. It also grows in the nearby Cimarron National Grassland. I've seen it growing in Barber County near Medicine Lodge, KS also in short grass prairie.

It grows in well drained open prairie mostly and appears to thrive in hot dry situations. I had a couple in my garden in loose well drained soil until they got shaded out by a near-by tree and they slowly died. While they were there, they never needed watering and they bloomed for long periods each summer. If we had an extended dro... read more


On Oct 18, 2007, tucsonjill from Lincoln, NE (Zone 5a) wrote:

For me, this plant is a short-lived perennial; they usually grow for about 3-4 years and then need replacement. But for those years, they can't be beat. They put on a huge show of lemon yellow flowers in the late spring/early summer, a few scattered blooms during the high heat, and another flush in the early to mid fall. They take direct to reflected sun well, and are doing well in a fairly heavy soil. They do need supplemental water in our middle-desert summers.


On May 16, 2007, krdixon from Albuquerque, NM (Zone 7a) wrote:

This plant has grown to about three feet in diameter. It's one of the first bloomers in my garden and keeps yielding huge day-glow yellow flowers until late fall. It doesn't require much in the way of water, and has started volunteering around my garden (Albuquerque, NM).

Looks great trailing over walls and as a companion to lavender and sage.


On Nov 30, 2006, frostweed from Josephine, Arlington, TX (Zone 8a) wrote:

Lavender-leaf Sundrops Calylophus lavandulifolius is native to Texas and other States.


On Jun 15, 2004, lgreeno from Sierra Vista, AZ (Zone 8a) wrote:

likes alkaline,fast draining soil
VERY drought tolerant (uses very little water)
Good for xeriscape
Give plenty of room