Overview

Oenothera tetragona 'Yellow River' is a perennial in the genus Oenothera, part of the Onagraceae family. Oenothera tetragona 'Yellow River' grows best in full sun and partial shade, and tolerates well-drained soils and neutral and alkaline pH. Its UK hardiness is rated H5. Suggested uses include borders and wildlife gardens. It is native to eastern North America.

About the genus

Oenothera is a genus of about 160 species of herbaceous flowering plants native to the Americas. The genus includes common evening primrose, sundrops and gaura. It is the type genus of the family Onagraceae.

Wikipedia contributors, "Oenothera", CC BY-SA 4.0 — Oenothera

In the garden

Oenothera tetragona 'Yellow River' is a herbaceous perennial in the evening-primrose family, brought to gardens from eastern North America. It produces summer blooms between June and September and carries a mild fragrance that is noticeable when close to the flowers. The cultivar name identifies it within the species and is useful when sourcing plants. Provide a sunny to part-shade position and a freely draining soil with a neutral to alkaline pH; the plant prefers a moderate soil moisture rather than waterlogged ground. It is rated H5 — described as hardy in UK terms — so it will survive normal winter conditions in most garden situations where soil does not remain sodden. Situate where roots can drain freely and choose a spot with some shelter from prolonged wet. Use Oenothera tetragona 'Yellow River' towards the middle or rear of a mixed border or within a wildlife-focused planting where summer flowers are required. Its June–September flowering window gives reliable midsummer to early-autumn interest, and the mild-scented blooms reward close inspection rather than filling a whole garden with perfume.

Growing conditions

Best soil and position for Oenothera

Sunlight

full sun, partial shade

Soil type

well-drained

Soil pH

neutral, alkaline

Soil moisture

medium

UK hardiness

H5

Plant details

Oenothera tetragona 'Yellow River' size, habit and characteristics

Plant type

perennial

Suggested uses

borders, wildlife gardens

Native to

eastern North America

Fragrance

mild

Care notes

Pruning and caring for Oenothera tetragona 'Yellow River'

Cultivation

Prefers well-drained soil in full sun to partial shade. Tolerates drought once established.

Pruning

Cut back after flowering to maintain shape and encourage new growth.

Propagation

Seed, division

Frequently asked questions

From the Fenn Plants journal

• Gardening Jobs for AugustA short, honest list of August garden jobs worth doing — deadheading, ordering spring bulbs, light pruning and watering where it counts. Fenn Plants’s guide.
• Notes on DaffodilsWhen to plant daffodil bulbs in the UK, how deep, how to naturalise them in grass, why daffodils stop flowering (“blindness”), and why you should never mix cut daffodils with other flowers.
• Keeping Your NerveHow to garden through a heatwave — the best time to water, why deep soaks beat daily sprinkles, caring for pots and vulnerable plants, and why you can let the lawn go brown.

More in the Oenothera genus

• 
  Oenothera fruticosa 'Michelle Ploeger'Narrowleaf Evening Primrose
• 
  Oenothera missouriensisMissouri evening primrose
• 
  Oenothera odorataPrimrose
• 
  Oenothera tetragonaglaucous evening primrose
• 
  Oenothera tetragona 'Fyrverkeri'Evening Primrose
• 
  Oenothera tetragona 'Lady Brookborough'Primrose
• Gaura lindheirmeri 'Cool Breeze'
• Oenothera lindheimeri Baby Butterfly Dark Pink ('Uriblbp'PBR) (G)