Common name: Blue Wild Indigo or Blue False indigo, wild indigo, plains wild indigo, false indigo, baptisia, plains baptisia, rattlepod, rattlebush, rattlebush wild indigo
Scientific name: Baptista australis
Family name: Fabiaceae (Pea/Legume Family)
Description: Blue wild indigo is a native, perennial, deep-rooted warm season legume which reproduces by seed or rhizomes. The Cherokees have used the plant as a source of blue dye for their clothes.
Host plant to: Black-spotted Prominent moth, Henry’s Elfin moth (Callophrys henrici), Hoary Edge moth (Achalarus lyciades), Silver-spotted Skipper (Epargyreus clarus) Wild Indigo Duskywing (Erynnis baptisiae)
Native range: It occurs from Nebraska to Texas on the west to the eastern seaboard states. It is rarely found near the Gulf or Atlantic coasts.
Habitat: In Pennsylvania it is found in open woods, sandy floodplains and stream bands. It doesn’t grow well in shade. Baptistia australis prefers gravelly, sandy or well-drained loamy soils. It withstands prolonged droughts. Like many legumes it can fix nitrogen in the soil.
Height: may grow up to 5 feet tall and 3 feet wide, normally, it is about 3 feet tall and 2 feet wide
Light needed: full sun
Hardiness zones: 3 -10
Bloom period: In PA it lowers May – June
Bloom color: a beautiful deep purple-blue
Growing Tips: Collected seeds from plants growing in a native setting have an extremely low germination rate due to predation by weevils. The pods should be treated for insects before bringing them into a greenhouse or the seeds sorted prior to bringing them inside. If these precautions are not taken it is likely several dozen weevils will immediately escape when the pod is opened.
Like many other legumes it has a hard seed coat. The seeds must be scarified if germination is to occur within an artificial setting. Also, studies involving stratification and soaking the seeds a full day prior to planting show more success than scarification alone. The seeds normally germinate when the soil temperature nears 50 degrees Fahrenheit. After seedlings emerge they can be divided and further propagated.
Once it has become established blue wild indigo will remain healthy for several years. It is easy to maintain.
Blue wild indigo is unlikely to become weedy or invasive in most regions or habitats and rarely displaces other plants.
Photo credit: Donna Long © 2006
Resource: USDA Plant Fact Sheet/Guide Coordination Page http://plants.usda.gov/java/profile?symbol=BAAU