Oenothera biennis (also called Evening primrose)
Hardy herbaceous biennial grown for tall stems of cup-shaped yellow flowers. The flowers generally open in the evening and close partial or wholly during the day - although they are short lived, many flowers are produced. Evening primrose is popular in wildlife gardens as it attracts many beneficial flying insects, such as hoverflies and moths, which make use of its abundant pollen.
Oenothera biennis is also used in herbalism as a sedative tea.
Originally from NE America but naturalised in the UK.
Yellow flowers from early summer to first frosts.
Habit - upright, with basal leaves in a rosette. Tends to lean with age. H: up to 1.2m : up to .5m
Stem - round, green, straight and smooth.
Leaves - simple, alternate, spear-shaped, lacking stems.
Flowers - grow from leaf axils, yellow, cup-shaped with four petals. Stamens are prominent and produce much pollen.
Full sun to partial shade.
Remove seed heads if you don't want it to self seed. Cut back leaning stems when flowering has finished in autumn.
Plants will self seed freely and can be transplanted when young. This plant has a thick tap root and resents disturbance once it is established, so move it when it's still small.