blue wild indigo (Baptisia australis)
blue false indigo
blue wild indigo
plains wild indigo
rattlebush wild indigo
Baptisia caerulea Eaton & Wright
Baptisia confusa G. Don
Baptisia exaltata Sweet
Baptisia minor var. aberrans Larisey
Podalyria australis (L.) Willd.
Podalyria coerulea (Trew)Michx.
Ripasia caerulea (Trew) Raf.
Sophora australis L.
Sophora caerulea Trew
CONFIRMATION STATUS: Pending confirmation.
TAXONOMY: The currently accepted scientific name of blue wild
indigo is Baptisia australis (L.) R. Br.
NATIVE STATUS: Native, United States; Introduced, Canada.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: Blue wild indigo is a native, perennial, deep rooted warm season
legume which reproduces by seed or rhizomes. The plant is erect, rising
from a branched root system which has root tubercles. It branches at the
top with the flowers in an erect short terminal raceme at the pinnacle. The
stems are stout and glabrous. It may grow up to 5 feet tall and 3 feet wide. Normally, it is about 3 feet tall and 2 feet wide.
Leaves: The compound leaves are alternate and trifoliate and can be green,
bluish green, or greyish green. They are devoid of hairs and their margins
are smooth. Each leaflet is oblanceolate, although bluntly pointed toward
Flowers: The flowers are hermaphroditic, about ¾-1 inch long and may
range in color from light blue to deep purple, and have a typical structure
for a large pea flower. There is no scent to the to the flowers. Blue wild
indigo continues to grow after the blooming period.
Fruit/Seeds: The fruit is an inflated hardened pod from 1 to 3 inches long
and from 1/2 to 1 inch in diameter. When mature the pods contain a num-
ber of small seeds, which are loose. It is in leaf approximately one month
before flowering to one month after the pods have formed. In the autumn
when full maturity is reached the plant turns silvery-gray, and breaks off
from the root system at ground level. The pods stay with the plant for some
time while the wind tumbles it around to a new location. The leaves and
pods turn black upon drying. When it is growing if a leaf is crushed or
stem is broken the sap turns a slate blue color when exposed to the air.
Roots: Blue wild indgo tends to have a long, deep taproot system.
REGENERATION PROCESS: Blue wild indigo propogates itself by
reseeding. The rather large seeds fall to the ground only a short distance
from the mother plant. In addition, the root system consists of a central
taproot, with short rhizomes that help this plant to spread. With short
distance reseeding and rhizome spread, Blue wild indigo can form dense
HABITAT TYPES: Larger populations can be found along tree lines,
rocky open woodlands, bordering forested riparian areas and rocky banks
of rivers, and in open prairies, mesic black soil prairies, gravel prairies and
native hay meadows. Blue wild indigo adapts to many areas outside its
native habitat. In addition, it can withstand highly variable climate condi-
tions including freezing temperature extremes of negative 30 degrees
Fahrenheit for a short period without any ill effects.
SITE CHARACTERISTICS: Blue wild indigo does well in full to
partial sun; it does not grow well in shaded habitats. It prefers gravelly,
sandy or well-drained deep loamy soils. It does best in average moisture
levels but can withstand prolonged droughts. Like many legumes it can
fix nitrogen in the soil. It seems to have greater difficulty competing
against other kinds of plants in a naturalistic setting, and, like other wild
indigos, this plant is somewhat slow in becoming established (although
not a particularly difficult plant to establish).
SEASONAL DEVELOPMENT: Blue wild indigo bloom during the
late spring for about 3 weeks. Depending on the region it may flower
from April (in the south) through August (in the north).
GENERAL DISTRIBUTION: Blue wild indigo is a species primarily
located in the eastern portion of the United States, from Georgia north
through southern New England, and extends westward through the Ohio
Valley into the eastern part of the Prairie states. It does not naturally
occur along the Gulf Coast states and has only been documented in one
Canadian province - Ontario. It does not occur in the western Plains re-
gion, the south- west (with the exception of Texas), the Rocky Mountain
region, the far western or northwestern states.
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: It is likely that Queen bumblebees are
important pollinators of Baptisia australis flowers. Other long-tongued
bees may visit the flowers occasionally, such as miner bees. Like other
wild indigos, the foliage of this plant may be consumed by the caterpillars
of a few species of skippers and related insects, including Erynnis baptisiae
(wild indigo duskywing), Achelerus lyciades (hoary edge), Dasylophia
anguina (black-spotted prominent), and Colias cesonia (southern dogface).
The adults of Apion rostrum (wild indigo weevil) feed on the flowers and
leaves, while the grubs of this insect feed on seeds. Generally, mammalian
herbivores avoid this wild indigo and others because the leaves are some-
It makes good ground cover in sunny locations because of its bushy habit,
extensive root systems and perennial life form. It is a native legume, fixes
nitrogen in the soil, and can be part of a good wildlife seed mixture when
native grasses and forbs are seeded.
Presently, blue wild indigo, is grown by many as an ornamental in outdoor
flower gardens or as a decorative border. It has become popular because it
grows well in many areas outside its native range when planted, does well
without watering, requires no fertilizer or pesticide treatments and needs
no pruning, can be very long-lived, and remains attractive throughout most
of the growing season.The pods have been used in dried flower arrange-
ments. When in bloom the brightly colored blue flowers arranged in spikes
make it very attractive. However, a bouquet of fresh cut flowers does not
last very long. The flowers and stems turn black as soon as they begin to
The Cherokees used the plant as a source of blue dye for their clothes.
Early pioneer settlers copied this practice. A common name, false indigo,
indicates it is not the true indigo plant (Indigofera tinctoria L.) which was introduced from the India subcontinent and cultivated for blue dye by
many land- owners during the early settlement of America. Some Indian
tribes used it for medicinal purposes. The Osage made eyewash from the
plant. The Cherokees would make a tea from it. A hot tea was taken as a
purgative and a cold tea to prevent vomiting. A pulverized root or hot tea
was held over a sore tooth to relieve the pain. Indian children would use
the dried pods with the loose seeds inside as rattles.
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