Oenothera flowers

Flowering hardy annuals, biennials and short-lived perennials. Long cultivated by herbalists and attractive to bees and butterflies.

Family: Onagraceae
Botanical Name: Oenothera
Common Names: Evening primrose, sundrops

Foliage: Deciduous, simple ovate or lanceolate, green leaves.

Flowers: Short-lived fragrant yellow, pink or white funnel-shaped flowers. Flowers open in the evening.

Flowering Period: Summer to early autumn (July to September).

Soil: Well-drained soil (sand or loam). Acid, alkaline or neutral pH.

Conditions: Full sun or partial shade. Plant in a west or south facing aspect, in a sheltered position.

Habit: Upright, spreading.

Type: Herbaceous perennial.

Origin: Americas

Hardiness: Hardy in the UK.

Planting and Growing Oenothera

Easy to grow. Plant out between autumn and spring. Thrives in any light, free-draining, moderately fertile soil, in full sun or partial shade.

Tall forms are useful for the mixed border. Smaller forms are suitable for the rock garden.

Taking Care of Oenothera

Water well in dry weather. Mulch in spring.

Pruning Oenothera

Deadhead to prolong flowering season. Cut the faded stems of perennials down to ground level in autumn.

Pull up and discard annuals and biennials at the end of the season.

Pests and Diseases

Leaves can be affected by powdery mildews and leaf spot. Root rot can occur on heavy waterlogged soils.

Propagating Oenothera

Sow seeds outdoors in a prepared seed bed in late spring. Move to final flowering positions in autumn.

Sow O. acaulis under glass in early spring.

Divide established perennials or take cuttings in early spring.

Popular Varieties of Oenothera

Some varieties are evening flowering, while others flower during the day.

Oenothera acaulis a popular rock-garden perennial with rosettes of deeply toothed, mid-green leaves. Large flowers, opening white then fading to deep rose-pink, from summer into autumn. Height 6in (15cm), spread 18in (45cm).

Oenothera biennis (common evening primrose) produces light yellow flowers with red sepals. Readily self seeds. Height to 30ft (1m). For sale at Crocus.

Oenothera fruticosa subsp. glauca (narrow leaved) is a perennial with pleasant mid-green, lanceolate leaves and golden yellow flowers, in June-August. Height from 2 to 3ft (60-90cm), spread 1ft (30cm). Varieties include:

  • 'African Sun' bright yellow flowers from May through to September. For sale at Van Meuwen.
  • 'Fireworks' yellow flowers opening from red buds.
  • 'Yellow River' a good free-flowering form. Height 2ft (60cm), spread 1ft (30cm).
  • 'Erica Robin' has pink-green foliage. Height to 1ft (30cm).

Oenothera speciosa (pink ladies, white/pink evening primrose) is a medium height creeping form with lance-shaped, mid-green leaves and open saucer-shaped flowers. Opening white during the day and turning pale pink in the evening. Height to 1ft (30cm).

Oenothera versicolor 'Sunset Boulevard' red stemmed with rich green, lanceolate foliage. The striking flowers are in whorls, vivid orange/red when fully open and when over, turn to red. For sale at Thompson & Morgan.

Oenothera macrocarpa is a low growing form with sprawling, lax foliage and large lemon-yellow flowers.

Oenothera missouriensis is a useful hardy perennial with trailing stems of lanceolate, mid-green leaves and large bell-shaped yellow flowers in summer. Height to 6in (15cm), spread to 18in (45cm) or more.

Oenothera tetragona a bushy branching perennial with ovate, mid-green leaves. Plentiful spikes of small yellow flowers in June-September. Height 2-3tft (60-90cm), spread 12-18cm. Cultivars include 'Highlight' a free-flowering form with wide, yellow blooms and 'Fireworks' with bright yellow flowers.