Overview
Swainsona is a genus of about 85 species in the legume family (Fabaceae), with all but one species endemic to Australia and a single species reaching New Zealand. The genus spans annual herbs, herbaceous perennials, and small subshrubs, growing from prostrate mats to upright stems 4-40 inches (10-100 cm) tall. Leaves are pinnately compound with 5 to 21 leaflets, often grey-green and covered in downy hairs that reduce water loss in dry habitats. Flowers are pea-shaped (papilionaceous) and held in upright racemes, ranging across red, pink, purple, mauve, white, and yellow depending on species; S. formosa, the Sturt's Desert Pea, carries blood-red blooms with a black central boss. Flowering follows rainfall and is concentrated in spring across most of the range. Seeds form in inflated or flattened pods typical of the family. Several species accumulate the alkaloid swainsonine, which is toxic to grazing livestock. Many Swainsona species are adapted to seasonally dry inland soils and are short-lived, dying back or perishing after seed set, which limits their persistence in cultivation outside well-drained, low-humidity conditions.
Native Range
Swainsona is almost entirely Australian, with species spread across every mainland state from coastal districts to the arid interior. A single species, S. novae-zelandiae, occurs in New Zealand.Suggested Uses
Used in native and water-wise gardens, rockeries, and containers across Australia, with the red-flowered S. formosa grown as a sprawling ornamental and in raised or hanging displays. Inland species feature in revegetation of dry, open ground.How to Identify
Appearance
Size & Dimensions
Height4" - 3'4"
Width/Spread8" - 3'4"
Bloom Information
Most species flower in spring (September-November in the southern hemisphere), and desert species bloom opportunistically within weeks of significant rainfall at any season. Flowering lasts several weeks, after which plants set seed and many annual or short-lived species die back.
Detailed Descriptions
Flower Description
red, pink, purple, mauve, white, or yellowFoliage Description
grey-green to greenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Water & Climate
Water Needs
Drought Tolerance
Drought tolerant when established