Evening Primrose

Evening primroses may have a rather bedraggled appearance through the day, but they more than make up for this at night. As soon as the sun becomes lower in the sky in late afternoon, their transformation begins. By early evening, petals have fully unfurled and bright yellow, cup-shaped flowers are displayed along tall, sturdy stems that rise above rosettes of foliage. When darkness falls, the luminosity of the flowers is accompanied by a sweet fragrance that entices moths and other nocturnal insects to visit. In late summer and early autumn, flowers often remain open all day.

ARCADIAN ARCHIVES
Oenothera (Evening Primrose)
Evening primroses may have a rather bedraggled appearance through the day, but they more than make up for this at night. As soon as the sun becomes lower in the sky in late afternoon, their transformation begins. By early evening, petals have fully unfurled and bright yellow, cup-shaped flowers are displayed along tall, sturdy stems that rise above rosettes of foliage. When darkness falls, the luminosity of the flowers is accompanied by a sweet fragrance that entices moths and other nocturnal insects to visit. In late summer and early autumn, flowers often remain open all day.
Botanically known as Oenothera, evening primroses usually behave as biennials. The most popular species, O. biennis, is native to many parts of North America where it grows in dry, sunny sites. It is also is grown commercially as a crop to provide the seeds that are used in the production of Evening Primrose Oil, the well known herbal medicine. Once this species has been introduced to your garden, it will more than likely stay with you. It self-seeds readily, establishing itself in colonies wherever it can find well-drained, stony conditions. Gravel paths or cracks in paving are favourite habitats but it does have the potential to become a nuisance because of the sheer abundance and spread of its seedlings. I keep it restricted to one small area of gravel where it mingles freely with opium poppies and a few Verbascum to create a very natural effect. In some urban areas, it has become naturalised on wasteland where soil is poor and arid: abandoned building sites provide the best conditions. It blooms from around the end of June until September, with the first flowers of the season opening on the middle of the 120 cm (4 ft) stem. By the time the flowers at the top of the stem are opening in late summer, seeds from the earliest flowers have already been released. If conditions are suitable, seedlings establish quickly; they will put on as much growth as they can in late summer and then produce flowers the following year. Root growth on seedlings is extremely rapid. In some areas of Europe, evening primrose used to be cultivated purely for the thick, fleshy roots that were harvested during the first year and eaten as a vegetable. For smaller gardens, there are several less vigorous evening primroses available. Oenothera acaulis is ideal for rock gardens or scree beds. This miniature species, reaching a height of only 15 cm (6 in), has trumpet-shaped, white flowers that open at night and then turn pink during the following day. Native to Chile, it is less hardy and requires a sheltered spot. Known as the Mexican evening primrose, Oenothera 'Siskiyou' is one of the prettiest cultivars. Large, pink, fragrant flowers are ornamented with purple veining and are displayed on stems around 45 cm (18 in) in height. It has a slightly lax habit, so when planted in groups, it provides fairly dense ground cover. These more refined evening primroses will require extra protection from wet or cold winters if they are to thrive.

Oenothera (Evening Primrose)