Large-flowered Evening-primrose (Oenothera glazioviana) — identification, habitat & look-alikes

Large-flowered evening-primrose is a tall roadside plant with broad yellow flowers that open near sunset. Although its parent species came from North America, it likely originated as a hybrid in European gardens and later escaped into scattered parts of the United States.

Appearance

Growth form: This grows an upright flowering stem about 1.6–5 ft (0.5–1.5 m) tall from a .
Leaves: The leaves are narrow to lance-shaped, often with a crinkled surface and widely spaced blunt teeth. Their midveins may be pale or reddish.
Flowers: Each broad yellow petal is about 1.4–2 in (3.5–5 cm) long, and the flower opens near sunset. The often show red stripes or a deep red wash, and the four-branched projects beyond the .
Flowering time: In North America it usually flowers from July through September, sometimes beginning in June or continuing into October.
Fruit: Upright narrow split to release dark, angular seeds.

Look-alikes

common evening-primroseOenothera biennis

Common evening-primrose usually has smaller petals, 0.5–1.2 in (1.2–3 cm), and its stigma sits among the anthers. Large-flowered evening-primrose has petals about 1.4–2 in (3.5–5 cm) long and a stigma that clearly extends beyond the anthers.

Why they get mixed upBoth are tall biennials with yellow flowers that open near sunset.

pinkladiesOenothera speciosa

Pinkladies has white-to-pink flowers with pink or red veins and spreads low by underground stems. Large-flowered evening-primrose has yellow flowers and an upright central stem.

Why they get mixed upBoth have four broad, notched petals and occur in open sunny places.

Where it lives

Typical habitats: roadsides
waste ground
open disturbed sites
Range: In the United States it is introduced and scattered from the Northeast and Great Lakes to parts of the West and South. Records include California, Oregon, Washington, several northeastern states, and parts of the Midwest and Southeast.
Preferred conditions: It grows in sunny, open, disturbed ground, generally from low elevations to about 2,000 ft (600 m).
Flowering: Flowers Jul–Sep
Flowers Jul–Sep

Life cycle

Reproduction: It is and can set seed without pollen from another plant.

Name and classification

About the name: It was also called Oenothera erythrosepala. Also called redsepal evening-primrose.

Conservation

IUCN Red List: NENot EvaluatedNot yet assessed

Culture and stories

Culture and stories: Hugo de Vries used this plant in his early mutation studies.

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