SCIENTIFIC NAME: Oenothera missourensis

USDA HARDINESS ZONES: 5-9

TYPE: herbaceous perennial

FAMILY: Onagraceae

HEIGHT AND WIDTH: 12" x 12"

Introduction:

Sometimes called Missouri Primrose or Ozark Sundrops, this short, showy perennial gives a real bang for the buck. Oenothera missourensis is valued for its four-petaled, silky yellow spring or early summer flowers. These plants grow in rough, tough places and are often used in rock gardens or along parking strips because of their hardiness. Prostrate, sprawling stems, to 10" long, bear soft, velvety, 5-inch leaves. Clear yellow flowers cover the short stems. Flowers are surprisingly large-3"-5" across-in proportion to the short, weak stems. Basically pest free, drought tolerant, and quick spreading, Oenothera missourensis loves sun and flowers from late afternoon to night time. Fragrant, funnel-shaped blossoms emerge from noticeably long-tapered red-streaked buds. Sometimes referred to as Oenothera macrocarpa.

Culture:

Zones 5 - 9

O. missourensis thrives on little or no care once established, becoming invasive if not controlled. It makes a good ground cover for dry slopes, rock gardens, or parking strips and grows best with full sun in well-drained alkaline soil (for the big, deep taproot). In fall, flower arrangers can gather the pinkish-tan seed capsules for dried arrangements-egg-sized, but light and papery-with 4 thin wings.

Propagation:

Seed and division

Problems:

If grown in moist, fertile soil can take over. Stems die back after bloom, which can lead to stem rot. Infrequently white fly invasion can be a problem (in wetter climates). Over watering can lead to powdery mildew.

A hornworn, the larval stage of a Hawk Moth, is a common problem with `Young Sundrops' Evening Primrose Oenothera fruiticosa cv. youngii.

Related Species:

Common sundrops (O. tetragonia, O. fruticosa), are show-stopping yellow species, both day-blooming with canary yellow flowers, which open in the morning beginning from early to midsummer. They range from 18 to 36 inches and present larger stands than O. missourensis. A smaller yellow form is Hooker Evening Primrose or Oenothera hookeri. There is a Pink Evening Primrose, Oenothera speciosa or O. berlandieri. A white flowering form exists and a selection, Siskiyou, that is lighter pink than speciosa. It is also more compact and more nearly everblooming.

Text References:

• Brenzel, Kathleen N., Ed. 1995. Sunset Western Garden Book. Sunset Publishing, Menlo Park, CA.
• Hyde, Barbara, 1993. Gardening in the Mountain West, Vol. I. Barbara J. Hyde, Inc., Longmont, CO.
• Hudak, Joseph, 1993. Gardening with Perennials Month by Month, 2nd Ed., Revised and Expanded. Timber Press, Portland, OR.
• Roth, Susan, 1997. Better Homes and Gardens New Complete Guide to Gardening. Meredith Corporation, DesMoines, Iowa.
• Tenenbaum, Frances, Ed., 1994. Taylor's Master Guide to Gardening. Houghton Mifflin, New York, NY.

Web Sites of Interest:

• Michigan State University Extension
• New Mexico State University
• Wisconsin University (information on edible characteristics of O. biennis)

Plant List - The Gardens at the Mesa County Extension Office - Colorado State University

The `Gardens at the Mesa County Extension Office'