Parcel
No. 11$4.50 Missouri Evening Primrose
Illustration of the No. 11 Missouri Evening Primrose seed packet: a kraft envelope with the Missouri Native Series stamp label and a SOW SEP–NOV postmark on the front, and the growing directions and label details on the back.
The packet

No. 11 in the Missouri Native Series

Missouri Evening Primrose

Oenothera macrocarpa

Missouri Native Series No. 11. Big yellow flowers open each evening for sphinx moths. A low glade plant for sunny, rocky spots.

$4.50packet

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  • Missouri native seed, packed for 2027
  • Postmarked to sow September to November
  • Grow Guarantee: if it doesn't come up after you follow the guide, we'll send a replacement

This one carries Missouri in its name: botanists once called it Oenothera missouriensis. It lives on the limestone glades and bluffs of the Ozarks, a low, sprawling plant rarely a foot tall, with big yellow four-petaled flowers that open in late afternoon and stay open through the night.

Sphinx moths find them in the dark. Each flower lasts a single night, but a plant keeps opening new ones from May into August. Give it full sun and the sharpest drainage you have: a rock garden, a slope, a wall edge or a gravel strip.

It’s the series’ one fall-postmark stamp. Sow it outdoors in fall and let winter do the rest. Each packet is hand-filled in St. Charles County, Missouri.

Good to know

  • Needs fast drainage. Plant it in a rock garden, on a slope, at a wall edge or in a gravel strip.

How to grow

  1. Find your sunniest, best-drained spot. Think rock garden, slope, wall edge or gravel strip. It grows on glades in the wild.
  2. Sow in fall. Between September and November, sow on bare, gritty soil and cover lightly, about 1/8 inch. Winter does the rest, and sprouts come up in spring.
  3. Missed fall? Sow between December and February, outdoors or in a winter-sowing jug. See our winter sowing guide.
  4. Water sparingly. Help seedlings through long dry spells their first summer, then let it be. It’s a dry-ground plant.
  5. Go out at dusk. The flowers open in late afternoon. Bring a flashlight and look for sphinx moths.

Good neighbors

Species from the series that grow well alongside Missouri Evening Primrose:

Questions

Why do the flowers only last one day?

That’s how the plant works: the Missouri Department of Conservation notes each flower usually opens in late afternoon and stays open until the next morning. A healthy plant keeps opening new flowers through summer.

Who pollinates it at night?

Flowers that open at night are usually pollinated by night-feeding bees and moths (MDC). Prairie Moon notes sphinx moths in particular.

Will it grow in clay?

It needs fast drainage. In heavy clay, plant it in a raised spot, on a slope or in a gravelly bed.

Does it need cold stratification?

Sources differ. Prairie Moon recommends 60 days of cold-moist stratification, while the Lady Bird Johnson Wildflower Center says no treatment is necessary. Sowing outdoors in fall or winter gives it a chill either way.

Sources for these facts