Hardenbergia violacea aka Coral Pea

Hardenbergia violacea is an evergreen climber in the pea family. Its common names include coral pea and Australian lilac. It comes from eastern and southeastern Australia, including Tasmania. It grows in open woods and heathland. Wild plants climb low bushes from coastal areas into nearby mountains. Gardeners grow it for its leaves and flowers.

In gardens, it reaches about 5–8 feet [1.5–2.5 metres] tall. Its spread is about 1.6–3.3 feet [0.5–1 metre]. Some plants make stems nearly 10 feet [3 metres] long. These stems trail across the ground or twist around nearby plants. Some forms grow as shrubs without twining stems. A long rootstock, shaped like a carrot, lies below ground. The oval leaves reach about 4.7 inches [12 centimetres] long. Plants may take five to ten years to reach full size.

Flowers hang in clusters from late winter into spring. Most are purple, though pink and white flowers also occur. Each flower measures about 0.4 inches [1 centimetre] across. Insects pollinate the flowers, and the plant forms seedpods. Its evergreen leaves and hanging blooms suit walls and supports. It also suits patio pots and gardens with a Mediterranean climate. In colder places, gardeners can grow it under glass.

Choose a sheltered site with sun or some shade. It needs moist soil that drains well. Sandy or loamy soil suits it, with acid to neutral pH. For pots, use equal parts loam-based compost, sharp sand, and leaf mould. Give plants under glass bright light, but shade them from hot sun. Water moderately during growth, and feed monthly with balanced liquid fertiliser. Keep the compost just moist in winter. Provide support, and prune after flowering. RHS rates it H3; PFAF lists USDA zones 9–11. It can withstand brief cold near 23°F [-5°C] when dormant.

RHS reports few disease problems, but several pests can attack. Watch for red spider mites, whiteflies, and slugs under glass. Boiled leaves yield a mildly sweet drink. Reports also describe past use of the roots for drinks. Flowers provide a grey-blue dye, and the plant fixes nitrogen. PFAF lists no known medicinal use or hazards. Useful Tropical Plants, however, reports that foliage may cause colic in horses. This warning means the sources do not establish safety for all animals.