The genus of Clianthus, a member of the leguminosae family, generally contains only two species: C. punicens and C. dampieri, sometimes called C. formosus. Growers often refer to the plant C. punicens as parrot's bill or parrot beak because the flower resembles the beak of the Kaka parrot, hence Kakabeak, the native name. The C. dampieri usually carries the common name of gloryvine, glory pea, and sometimes Sturt's desert pea; it has attractive scarlet flowers that often have a striking reddish black to black bump at the base of the upper petals.
Generally known as the pea family, the leguminosae family contains legumes, or nitrogen-fixing plants, characteristic of the Clianthus plants. Like most pea plants, they bear their kidney-shaped seeds in pods, typically about 2 inches (5 cm) long in the Clianthus plants. Botanists theorize that these pods help the plant to propagate by dropping off the plant and floating down waterways and by flying away on strong winds.
The feathery appearance of the Clianthus foliage is because of the pinnate leaves, meaning that the leaves grow in small leaflets that branch from the main leaf stem. Generally, the plants are evergreen with grayish hairs covering the mid to dark green leaves, giving the leaves a grayish appearance. Glory pea plants have hairy, green leaves that are 5 to 7 inches (12 to 18 cm) long with nine to 21 oval hair-covered leaflets branching from the stem. Parrot's bill plants often have leaves similar to the glory pea plants, up to 6 inches (15 cm) long, with 13 to 25 narrow, oblong, and dark green hairy leaflets.
The flowers of Clianthus plants resemble lobster claws, which is another common name for the plants. Most of the flowers of the parrot's bill consist of a group of crimson flowers, each having a blackish bulbous mark on the upper petals. Some of the varieties do not have the black spot. The glory pea's flowers are red, rosy-pink, or white, depending on the variety. Each of the flowers dangle from the main stem in raceme clusters.
The species name dampieri represents one of the two explorers who discovered it. The Latin name references William Dampier, who reported discovering it in 1688. The common name Sturt's desert pea alludes to Captain Charles Sturt, who rediscovered it in 1844. In modern gardens, gardeners often plant the natural creeping plant as a ground cover and in rock gardens. It thrives in regions where the temperature averages between 32°F and 85°F (0° and 29°C).
The Clianthus plants are native to areas of Australia and New Zealand. It is rare to find the plant in the wild in New Zealand, where it usually grows at the edges of forests and flaxland; on cliffs and bluffs; and at the edges of waterways, such as streams, rivers, and lakes. Most botanists list the plants as endangered. It is declining in the wild because the natural habitats have been eradicated, animals have overgrazed the native areas, and the brown snail, which is an introduced species, ravages the plants.
The strange design of the flower may factor into its ability to self-pollinate. The flower has both female and male reproduction organs. Many botanists believe the beak-like curve of the petals allow the dry pollen to roll down to the tip of the stamen, where it pollinates the seed. Others think birds, such as the bellbird and tui, pollinate it. In captivity, growers propagate the plant by seeding or by rooting stem cuttings.
Sturt's desert pea is sometimes classified as Swainsona formosa of the fabaceae family. In 1961, South Australia adopted it as its floral emblem. When used in gardens, especially outside of its natural region, growers often graft it onto another plant's roots to ensure successful growth. Usually gardeners raise it in hanging baskets and containers where the climate is too cold for it to survive. In a suitable climate, gardeners sometimes grow it in raised beds, terraces, or trellises, thereby enhancing the effect of the colorful, dangling flowers.