False Blue Indigo

Description

Baptisia australis, also known as false blue indigo or wild blue indigo (and many other common names), is a member of the family Fabaceae. It is a legume and fixes nitrogen, improving the soil. Easy to grow in Zones 3-10, this ornamental plant reaches 3-5 feet with alternate gray-green leaves that feature clover-like leaflets. In early summer, flower spikes in light blue to violet appear above the foliage. The seed pods appearing in late summer are attractive and useful in flower arrangements.

Growing Conditions

Easy to grow, B. australis prefers well-drained soil in sun or light shade. It prefers slightly acid soil but will do well as long as the soil is well-drained. It is a long-lived plant, and it requires no chemical input (fertilizer, pesticides) and needs no pruning. Once established, this plant is virtually trouble-free. Wild Blue Indigo is deer-resistant and tolerates heat, drought, and humidity. The deep taproot makes it difficult to transplant.

Maintenance

If there is no interest in having seed pods, the flowering stems can be cut back by about one-third after flowering is complete. This will make a slightly more compact plant, and it should look good until winter. The foliage should be cut to the ground in fall or early spring.

Ecological Value: Wildlife, Insects, Etc.

The larvae of numerous butterfly species will use Baptisias as a host plant. Examples are orange sulphur, clouded sulphur, frosted elfin, eastern tailed blue, hoary edge, and wild indigo duskywing.

Landscaping

B. australis can provide borders or masses or be an attractive specimen in a home garden. Since B. australis is tall, it will work well at the back of the border.

Ethnobotany

The Cherokee people used the flowers as a source of blue dye. Teas made from the roots were thought to alleviate toothaches and nausea. Dried seed pods, which contain many seeds, are also used as rattles. The Osage people made an eyewash from this plant.

Pests and Diseases

A parasitic weevil will infest the seed pods. This does not affect the ornamental quality but may impact starting new plants from seed. There is an alkaloid in the plant which makes it toxic to many insects, although butterfly larvae appear to be unaffected.

Varieties

There are cultivars of this plant, such as "Purple Smoke and Twilight Praireblues," and there are three naturally occurring varieties, var. aberrans, var. australis, and var. minor. Hybrid Baptisias are appearing in the marketplace.

Companion Plants and Suggestions for Pairings

Wild Blue Indigo combines well with native ornamental grasses, as well as white and blue garden plants.

References

USDA-NRCS Plant Guide - Blue Wild Indigo

Clemson University Cooperative Extension, Home and Garden Information Center - Baptisia, False or Wild Indigo

University of Wisconsin Extension - Blue False Indigo, Baptisia australis

Authors: Judy Owen and Jay Holcomb