Guide to Growing Wild Indigo and Rattleweed

Plants of the Baptisia genus are very large (up to 2 meters) hardy perennials that are native to North America.

Some of the common names include wild indigo, Rattleweed, Blue false indigo and False indigo plant.

Depending on the species they may flower in late spring or early autumn.

When they do flower wild indigo plants have flowers similar to sweet peas, blue, white or yellow in colour, along very long slim stalks.

Baptisia australis (Blue Wild Indigo / Blue False Indigo plant) by My Garden.

Baptisia leucophaea (Cream) Wild Indigo photograph by Frank Mayfield.

Quick Baptisia Plant Growing and Care Guide

Common Names: Wild Indigo: Blue, white, hairy. False Indigo, Rattleweed, Indigo weed, Horse fly weed.
Life Cycle: Hardy perennial.
Height: 16 to 72 inches (40 to 180 cm).
Native: North America.
Growing Region: Zones 3 to 9.
Flowers: Species dependent: Late spring and early summer.
Flower Details: White, blue. Pea-like. On top of long thin spike-like stems.
Fruit: Blue-black. Pods. Oblong. Summer through autumn.
Foliage: Herbaceous. Trifoliate, Compound, Simple. Alternate. Grey-green. Blue-green. May be Cordate and hairy.
Sow Outside: 1/4 inch (6 mm). Start of spring or late autumn. Spacing 24 to 36 inches (60 to 90 cm).
Sow Inside: Seeds should be soaked for one day. Use peat pots. Germination time: one to seven weeks. Temperature 70°F (21°C). Six or seven weeks before expected last frost. Transplant outdoors following the last frost or at the start of autumn.
Requirements: Full sunlight, partial or light shade. Good drainage. Soil pH 5.5 to 7.0. Sandy soil. Can survive in dry soils. Provide support. Water during prolonged dry spells. Has very deep tap roots so do not disturb. Cut back dead leaves in the autumn to slow leaf fall. Propagate: dividing in the spring in cool areas or in the winter in warmer areas.
Miscellaneous: Named Blue false indigo due to its use as a dye when True indigo (Indigofera tinctoria) is not available.

How to Grow Baptisia species such as Wild Indigo

When planting Baptisia outdoors it is best to sow out the seeds at a depth of 6mm either in the early spring or late in the autumn. If planning to grow wild indigo indoors first then they should be sown in peat pots six to eight weeks before planning to transplant into the garden.

Baptisia species can take from one to five weeks to germinate. Initially the seeds should be soaked in warm water for one full day, the seed should then be chipped at with a knife, and a temperature of 21 to 24 degrees Celsius maintained from then on.

Wild indigo seedlings and other Baptisia plants should then be planted out at a spacing of 60 to 90 cm into a sunny or lightly shaded area of the garden; ideally with a well drained soil of pH of 5.5 to 7. Baptisia seedlings can either be planted out in the early autumn or after the last frost of spring.