Swainsona galegifolia
smooth darling pea
Overview
Swainsona galegifolia is an upright perennial legume 12-40 inches (30-100 cm) tall, branching from the base into slender, mostly hairless green stems. The pinnate leaves are 2-5 inches (5-13 cm) long, divided into 11 to 25 small oblong leaflets. Pea-shaped flowers about 0.5-0.8 inch (12-20 mm) long are carried in upright open racemes held above the foliage, in shades of purple, red, pink, and occasionally white. Flowering runs mainly through spring and summer and is followed by inflated, papery pods 0.8-1.2 inches (20-30 mm) long that hold many seeds. The plant grows from a deep taproot and tolerates dry conditions, dying back in drought and reshooting after rain. It occurs in grassland, open woodland, and disturbed ground across eastern Australia. The foliage contains the alkaloid swainsonine, which poisons grazing livestock and causes a wasting nervous condition known as Darling pea poisoning. The species can spread on grazing land where stock leave other feed, so it is treated as a pasture weed in some districts.
Native Range
Swainsona galegifolia is native to eastern Australia, from Queensland through New South Wales into Victoria. It grows in grassland, open woodland, and disturbed ground, often on clay and loam soils.Suggested Uses
Swainsona galegifolia is grown in native and dry-climate gardens for its spring and summer pea flowers and is used in grassland restoration in eastern Australia. On grazing land it is managed as a livestock-poisoning weed rather than encouraged.How to Identify
Appearance
Size & Dimensions
Height1' - 3'4"
Width/Spread1' - 2'
Reaches mature size in approximately 2 years
Bloom Information
Pea flowers open mainly in spring and summer, roughly September to February in eastern Australia, with some flowering after summer rain. They are held in upright racemes in purple, red, pink, or white. Inflated papery pods follow and dry as the seed ripens.
Detailed Descriptions
Flower Description
purple to redFoliage Description
greenGrowing Conditions
Sun Requirements
Requires 6-10 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
Swainsona galegifolia grows in full sun on free-draining clay or loam soils and tolerates heat and extended dry periods once established. It is grown from seed, which germinates more readily after scarification, and forms a deep taproot in its first year. Plants need little water once established and can rot in wet, poorly drained ground. It withstands light to moderate frost in USDA zones 8-10, dying back in cold and reshooting in spring. The foliage contains swainsonine and poisons grazing animals, so it is regarded as a hazard on grazing land and managed as a weed on pasture. Cutting back after flowering keeps growth compact and limits seeding.Pruning
Cutting plants back after the main flush extends flowering and keeps growth bushy. Removing spent racemes before pods ripen reduces self-seeding. Plants reshoot from the base after being cut back.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
summer
Container Growing
✓ Suitable for container growing
Minimum container size: 3 gallons