Purple Swainson-pea Plant Care

Swainsona purpurea (A.T.Lee) Joy Thomps.

Updated · Sources · How we source care data

Swainsona purpurea, commonly known as purple Swainson-pea or purple Darling pea, is a species of flowering plant in the family Fabaceae and is endemic to arid areas of inland Australia. It is an erect or spreading annual or perennial plant with imparipinnate leaves with 3 to 11 mostly linear or elliptic leaflets, and racemes of 3 to about 20 purple flowers.

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Water

Every 7–10 days

Light

Full sun to partial shade

Temp

50–80°F

Humidity

40–70%

At a glance

How do you care for Purple Swainson-pea?

Plant Purple Swainson-pea in full sun to partial shade (USDA zones 12a) and water a young shrub every 7–10 days until it is established. It tolerates temperatures of 50–80°F (10–27°C). Fertilize it every 6 months during the growing season.

Where Is the Purple Swainson-pea Native To?

Native range1 country

What Is the Purple Swainson-pea?

Purple Swainson-pea (Swainsona purpurea) belongs to the Fabaceae family within the Swainsona genus. Purple Swainson-pea is native to arid areas of inland Australia. Purple Swainson-pea is also known as Purple Darling-pea.

Purple Swainson-pea displays a bushy perennial shrub growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. Purple Swainson-pea produces showy pea-like flowers in various colors.

Leaf size: approximately 4 inches.

How Often Should You Water a Purple Swainson-pea?

Water a young or newly planted Purple Swainson-pea every 7–10 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established shrubs mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.

Watering Frequency

Every 7–10 days

Until established; then in dry spells

What Light Does the Purple Swainson-pea Need?

Purple Swainson-pea thrives in full sun to partial shade.

Light Requirement

Full sun to partial shade

What Temperature and Humidity Does the Purple Swainson-pea Prefer?

Swainsona purpurea tolerates temperatures of 50–80°F. Purple Swainson-pea prefers humidity levels of 40–70%.

Temperature

50–80°F

Humidity

40–70%

What Soil Mix Works Best for a Purple Swainson-pea?

Well-draining sandy loam with added organic matter. Good drainage is essential for Purple Swainson-pea to prevent waterlogging, which leads to root rot and fungal issues.

How Often Should You Fertilize a Purple Swainson-pea?

Feed Purple Swainson-pea every 6 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established shrubs in good soil often need little extra feeding, so let weak growth or pale foliage guide you.

Stop feeding by late summer so new growth can harden before winter.

Fertilizing

Every 6 months

During the growing season

The PlantoScan app can remind you when to water and when to fertilize each plant.

Where Should You Plant a Purple Swainson-pea?

Choose a spot with full sun to partial shade and well-draining sandy loam with added organic matter. Avoid low spots where water collects after rain.

Purple Swainson-pea is suited to USDA Zone 12a.

Plant container-grown or balled-and-burlapped shrubs in spring or early autumn, setting the root flare at soil level, and water well after planting.

How Far Apart Should You Plant a Purple Swainson-pea?

Purple Swainson-pea can spread to about 2 ft (0.6 m) and reach about 3 ft (1 m) tall. Space plants about 2 ft (0.6 m) apart so mature crowns don't crowd each other, and plant at least half that distance from buildings, fences and paths.

Planning a row or hedge? Try the plant spacing calculator.

How Do You Prune a Purple Swainson-pea?

Prune Purple Swainson-pea while it is dormant in late winter: first remove dead, damaged and crossing branches, then thin lightly for shape.

If it flowers in spring, prune right after flowering instead so you don't remove next year's buds. Never take off more than about a quarter of the shrub in one year.

How Do You Care for a Purple Swainson-pea in Winter?

Purple Swainson-pea is frost-tender (hardy to USDA zone 12). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

How Do You Propagate a Purple Swainson-pea?

Purple Swainson-pea can be propagated through seeds, stem cuttings. Similar propagation techniques also apply to swainsona acuticarinata plant care, which shares the same genus.

Is the Purple Swainson-pea Toxic to Pets and Children?

Pet safety not verified

The ASPCA does not list Purple Swainson-pea, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.

This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.

See all plants toxic to cats and plants toxic to dogs.

What Pests and Diseases Affect the Purple Swainson-pea?

Purple Swainson-pea is susceptible to aphids, whiteflies, spider mites. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.

Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.

What USDA Hardiness Zone Does the Purple Swainson-pea Need?

Purple Swainson-pea grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Purple Swainson-pea is native to arid areas of inland Australia. In cooler regions, grow Purple Swainson-pea as a houseplant or bring it indoors before the first frost.

Hardiness Zone

Zone 12a

Keep exploring plants

Purple Swainson-pea is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.

It belongs to the Swainsona genus — compare its care with other Swainsona species on PlantoScan.

Swainsona is part of the Fabaceae plant family — browse all Fabaceae genera and species.

Purple Swainson-pea thrives in bright light and direct sun — see other bright-light plants.

More Swainsona Species

Other Swainsona species in PlantoScan's care catalogue share similar watering, light, and soil preferences:

Sources

  • Scientific name & taxonomy: Swainsona purpurea (A.T.Lee) Joy Thomps., family Fabaceae (first published in Telopea 4: 4 (1990)) — World Flora Online record, IPNI name record.
  • Pet toxicity: Pet safety not verified: the ASPCA does not list Purple Swainson-pea, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
  • Hardiness zone: USDA Zone 12a, calculated from the plant's minimum temperature.
  • Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.

Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.

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