Blue False Indigo
Baptisia australis


Baptisia australis, commonly known as Blue Wild Indigo or Blue False Indigo, is a herbaceous perennial in the pea family. It is native to much of central and eastern North America and is particularly common in the Midwest, but it has also been introduced well beyond its natural range. The plant may attain a height of 5 ft and a width of (3.2 ft, but most often it is encountered at about 3.2 ft with a 2 foot spread. It is well known in gardens due to its attractive pea-like, deep blue flowers that emerge on spikes in the late spring and early summer. It requires little maintenance and is quite hardy. The seed pods are popular in flower arrangements, which also contribute to its popularity in cultivation. Several American Indians tribes made use of the plant for a variety of purposes. The Cherokees used it as a source of blue dye, a practice later copied by European settlers. They also would use the roots in teas as a purgative or to treat tooth aches and nausea, while the Osage made an eyewash with the plant..

The name of the genus is derived from the Ancient Greek word bapto, meaning “to dip" or "immerse”, while the specific name australis is Latin for "southern". Additional common names of this plant exist, such as Indigo Weed, RattleweedRattlebush and Horse Fly Weed. The common name "blue false indigo" is derived from it being used as a substitute for the superior dye producing plant, namely Indigofera tinctoriaB. australis grows best in lime free, well-drained stony soil in full sun to part shade. Naturally it can be found growing wild at the borders of woods, along streams or in open meadows. It often has difficulty seeding itself in its native areas due to parasitic weevils that enter the seed pods, making the number of viable seeds very low.

Description

B. australis is an herbaceous perennial that reproduces both sexually and asexually by means of its spreading rhizomes. The plants are erect and emerge from the rhizomatic network. The roots themselves are branched and deep, which helps the plant withstand periods of drought. When dug up they are woody and black in colour and show tubercles, wart-like projections found on the roots. The plants branch extensively about halfway up. The stems are hairless. If they are broken, a sap will be secreted that turns a dark blue upon contact to the air.

The trifoliate leaves are a grey-green in colour and are arranged alternately. The leaves are further divided into clover-like leaflets that are obovate in shape, or wider towards the apex. Flower spikes appear in June. Emerging at the pinnacle are short, upright terminal  racemes  that have pea-like flowers that vary in colour from light blue to deep violet. The flowers, which bloom from April through August depending on the region, are bisexual and are roughly 1 inch long. The fruit is a bluish black inflated and hardened pod that ranges from 1 to 3 inches in length by 1/2 to 1 inch. They are oblong in shape and are sharply tipped at the apex. At maturity they will contain many loose seeds within. The seeds are yellowish brown, kidney shaped and about .08 inches in size.The leaves emerge about one month before flowering and are shed approximately one month after the pods form. Once the seeds are fully mature, the stems turn a silverish grey and break off from the roots. The pods stay attached and are blown with the stems to another location.

Uses

Baptisia has been used as an antiseptic, anticatarrhal, febrifuge,and stimulant purgative. This plant is said to stimulate immune responses to infection, and is used for ear, nose and throat problems,laryngitis, tonsillitis, as a wash for mouth ulcers, and a douche for leucorrhea. Baptisia is considered toxic. Do not use this plant unless under the supervision of a trained qualified practitioner. It is not for long term use and not to be used if pregnant. The bark of the root is harvested in autumn. The leaves may be harvested anytime.

Native Americans used root tea of False blue indigo as an emetic and purgative. A cold tea was given to stop vomiting, a root poultice used as an anti-inflammatory, and bits of the root were held in the mouth to treat toothaches. Baptisia species are being investigated for use as a potential stimulant of the immune system. A decoction of stems has been used for pneumonia, tuberculosis and influenza, tips of stems combined with twigs of the Utah juniper, Juniperus osteosperma, have been used as a kidney medicine. Baptisia has also been used as a tea (tisane) for smallpox and externally as a cleansing wash. Trials using the extract of Baptisia to treat typhoid fever were made in the early 19th century. Current uses for this plant include: infection of upper respiratory tract, common cold, tonsillitis, stomatitis, inflammation of mucous membrane, fever, ointment for painless ulcers, inflamed nipples. Over-medicating will produce vomiting, diarrhea, gastrointestinal complaints, and spasms due toquinolizidine alkaloid content.

The pods are utilised in dried arrangements. Wild blue indigo is said to repel flies when kept near farm animals. Hang a bunch of Baptisia off the tack of a working animal. The plant is also used in Witchcraft in spells or rituals of protection. Keep a leaf in your pocket or add to an amulet for protection

Cultivation

B. australis is the most commonly cultivated species in its genus in North America, and it is also cultivated beyond its native continent in other areas such as Great Britain. It is considered a desirable plant in the garden due to its deep blue to violet spring flowers, the attractive light green compound leaves, and also for the somewhat unusual oblong fruits that emerge in the late summer. They grow to about 3 to 4 feet tall with a similar spread. Like other members of the genus, they have very deep taproots, which makes them quite difficult to move once planted. The plants thrive in full sun and require water only in times of low rainfall. One slightly negative feature it that the leaves tend to drop early in the fall, but this is may be avoided by cutting the dead stems as they die back. It is hardy in USDA zones 3 through 8. It is commonly employed as a border plant in gardens. While there are no commonly available cultivars, several hybrids involving B. australis have been created, such as Baptisia 'Purple Smoke', which is a cross with Baptisia alba. The variety Baptisia australis var. minor in also used occasionally in gardens. It is much shorter at only 1 to 2 feet in height, but the flowers are equal in size.

Eating seeds may be toxic, especially in children

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Blue False Indigo
Photo by Libby Wilkes

Rebecca Jordi
Horticulture Agent IV
County Extension Director
Contributing Editor
email: rljordi@ufl.edu