Indigofera australis
Australian indigo
Australia (all mainland states and Tasmania)
Overview
Indigofera australis is an open, spreading shrub in the pea family (Fabaceae), growing 3-6.5 feet (1-2 m) tall and about as wide, with slender, arching branches. The blue-green leaves are pinnate, 2-4 inches (5-10 cm) long, with 9 to 21 oval leaflets that give the plant an airy texture. From late winter into spring it carries sprays of purple-pink to mauve pea flowers, each about 0.4 inch (10 mm) long, in loose racemes 2-4 inches (5-10 cm) long along the stems. Narrow cylindrical pods follow. It occurs widely across Australia, in all mainland states and Tasmania, growing in open eucalypt forest and woodland, often as an understorey shrub on a range of soils. As a legume it fixes nitrogen and regrows readily after fire from a woody base. It tolerates drought and light frost once established but can be cut to the ground by hard frost, reshooting from the base in spring. The form is loose and somewhat sparse, and plants can become straggly without periodic pruning. In deep shade flowering is reduced and growth becomes leggy. Despite the common name, the species yields little usable dye compared with the commercial Indigofera spp. species.
Native Range
Indigofera australis is native across Australia, occurring in every mainland state and in Tasmania. It grows in open forest and woodland, commonly as an understorey shrub on sandy, loamy, and clay soils.Suggested Uses
Grown as an understorey or filler shrub in native and woodland gardens, in mixed shrub borders, and on dry slopes. It suits informal screening and habitat plantings, where its flowers draw native bees. The light form blends with grasses and other open shrubs.How to Identify
Appearance
Size & Dimensions
Height3' - 6'6"
Width/Spread3' - 6'6"
Bloom Information
Purple-pink to mauve pea flowers open from late winter into spring, roughly August to November in the native range. Flowering continues over several weeks in loose sprays along the branches. Bloom is reduced in shaded positions.
Detailed Descriptions
Flower Description
purple-pink to mauveFoliage Description
blue-greenGrowing Conditions
Sun Requirements
Requires 4-8 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
Care & Maintenance
Care Guide
Grow in full sun to part shade in free-draining sandy, loamy, or clay soil. Water during establishment, after which the plant tolerates dry periods. As a phosphorus-sensitive legume, it needs only low-phosphorus native fertiliser. Hard frost can cut the plant back, though it reshoots from the woody base in spring. Pruning after flowering limits legginess and keeps the form dense. Growth is most active in warm weather with occasional deep watering.Pruning
Prune after flowering, cutting stems back by up to one-third to maintain a dense, rounded shape and limit straggly growth. The plant responds to hard renewal pruning and reshoots from the base. Old, woody specimens can be cut low to rejuvenate them.Container Growing
✓ Suitable for container growing