Blue milkweed

Description

Oxypetalum coeruleum is a species of flowering plant, native to South America from southern Brazil to Uruguay. The synonymous name Tweedia caerulea is also used. Growing to 100 cm (39 in) long, it is a straggling evergreen perennial with heart shaped, gray-green, downy leaves. It is grown for its clear pale blue, star-shaped flowers, which are long lasting and cut well. The summer flowers age to purple and are followed by 30 cm (12 in) long, boat-shaped seed pods. The seeds have downy parachute-like tufts (cypsela). The cultivar 'Alba' has white flowers, while 'Rosea' has pink flowers. Oxypetalum coeruleum requires full sun in a well-drained soil that is dry. Propagation is via seed. With a minimum temperature range of 3–5 °C (37–41 °F), it can be grown outdoors in a frost-free, sheltered environment. Alternatively it can be grown as an annual. This plant has gained the Royal Horticultural Society's Award of Garden Merit. Oxypetalum is a genus of flowering plants in the family Apocynaceae, first described with this name in 1810. The genus is native to South America.