Oenothera is a member of the Onagraceaea family, commonly known as Evening Primrose. The most well-known evening primroses have yellow flowers but O. speciosa has delicate pale pink blooms which attract lots of pollinating insects. The blooms of most of the species open in the evening and close in the morning with some exceptions which include yellow flowering O. fruticose (Sundrops) which open during the day.
Common names include Pink Ladies, Pink Evening Primrose, Showy Evening Primrose and Mexican Primrose.
Once established, Pink Lady is surprisingly drought-tolerant although in very dry conditions the flowers are often smaller. In a severe drought it will become dormant. Occasional watering and a location which receives full sun (Pink Lady will not flower in the shade) will ensure a sea of large delicate flowers nearly all year round. The blooms which have four petals are usually veined with darker pink or red and have a yellow ‘eye’.
It is used in landscaping for preventing soil erosion in dry climates, especially on banks and steep slopes. Although the downy stems look delicate above ground, below ground is a different story. Pink Lady spreads by creating a thick, impenetrable mesh of roots which can choke other plants. The mass of foliage, which can grow to around half a metre tall, can also smother everything around it. It is native to the grasslands of the US and North East Mexico and in the wild is kept in check by grazing deer, horses and cattle. However without natural checks on its growth, it will spread to form an extensive colony. Therefore, in a small garden or patio, it is probably best to grow it in a container.
All parts of Pink Lady are edible and the leaves, which have a better flavour when young, can be used raw in salads or cooked like spinach.
Propagation is dividing the root ball or by collecting the papery, winged seeds as the pods dry on the plant.