Its name is interesting in itself. With a common name of "blue false indigo," it is no surprise that its lupine-like blossoms are blue. (Those lupine-like blossoms give rise to yet another name: redneck lupine.) B australis has always been used as a dye; the plant's sap turns an inky blue and blue dye can be made from its roots. Please note that this blue dye is inferior to dye made from "real" true indigo, Indigofera tinctoria. True indigo is native to Asia, which is where the name Indigo came from, meaning it was imported from India. Indigo came to be the name of the dye, and then the name of the color. Blue denim was originally dyed with Indigo dye.
But when settlers arrived in the New World, they found the locals dyeing things blue with a different plant, and called it "false indigo." It wasn't as effective as true indigo for dyeing clothes, but it was better than nothing. So it was "false" Indigo, "wild" Indigo, or even "blue wild indigo," not True Indigo. And don't get it confused with this False Indigo, which is another plant with a very similar name but a rather different habit.As for the Baptisia part of the name, it comes from the Greek root bapto- meaning to dip or to immerse. That's where we get the words for baptise and baptist. This plant was called Baptisia because people were dipping their cloth in extracts from it! The australis part means "southern," but Blue False Indigo is comfortable in many different parts of the continent.
That's where the correct binomial name of False or Wild Indigo comes from; Baptisia australis. Indeed, the flowers are extremely blue, nearly purple-blue-black. If you're not looking to dye things blue (like most of us in the 21st century), you will find Baptisia to be garden-friendly oramentals. They are tough once established, and feature deep blue flowers in late spring to early summer.
Baptisia grows to be a sturdy plant the size of a small shrub or a large plant. Like most of the plants in the Papilionaceae or legume family, Baptisia is a nitrogen-fixer. Other legumes I'm sure you are familiar with include peanuts, peas, sweet peas, soybeans, and so forth—all these garden plants and commercial crops help return nitrogen to depleted areas. So if your soil is poor, Baptisia won't mind, and it may actually make it better. Blue False Indigo dies back to the ground in the autumn, but perks right up every spring.
Blue False Indigo grows best in full sun, and once established, is difficult to move. Like the rest of the Papilionaceae family, Baptisia grows a long, tough taproot. Think of transplanting Sweet Peas (hard) or Bluebonnets (also hard). These are all plants which do best sown where they are to grow.
[As for dividing plants with a long tap root, generally speaking you can do it as long as the new, divided-off plant has a bit of root and a bit of leaves. You will find that plants with large tap-roots need to get bigger before you try (or need) to divide them. Whereas you can divide a coreopsis or a coleus as soon as there are enough leaves to sustain the donor plant, these large tap-rooted plants need to be allowed to develop tap roots for years before they can spare enough to make a new plant with. On the other hand, the tap-rooted plant is far more drought-tolerant than coleus because with all that tap root for storage to draw on, the plant can make it through tough times more easily.]
The species plant (pictured in the thumbnail photo, top right, © hczone6) has the signature blue blooms and gray-blue-green foliage, with large blue flowers resembling those of a pea plant. It blooms for a short while in May-July, depending on location, but the remainder of the time it is an attractive upright spreading herbaceous shrub.
Above left is a closer view, ©Perennial Resource™, please click the image for an enlargement. People agree that as foliage, Baptisia are handsome garden specimens. Leaving the spent blossoms on, however, allows for intriguing rattling dark fruit which are used in flower arrangements. (Photo at right, please click to enlarge, © hczone6.) Take them off in the fall or when they change color if you don't like the architectural appeal or their greyish silver color. The dried seed pods rattle in the wind, giving rise to yet another common name, rattleweed.
Blue False Indigo was chosen as the 2009 Kentucky Wildflower of the Year, although it is not as common in Kentucky as it is other dryer places. Next, it got the nod from the Perennial Plant Association that it was the Plant of the Year for 2010. Finally, it was awarded the Royal Horticultural Society Award of Garden Merit for 2013, which is certainly a ways out of its natural habitat. Here is a native plant that is good-looking as well as well-behaved. It demands only a well-drained, sunny location and enough space dedicated to it long-term that it can feel at home.
Blue Wild Indigo is resistant to most pests and is generally not favored as a food plant by deer or livestock. Give it lean, well-draining soil and sunshine. If things are very dry you might give it a drink, especially in its first few years. Butterflies and bees, however, are fond of the blossoms, if you have visitors that early in the summer.
Baptisia australis var. minor is a variety with a smaller overall stature (18-24 inches instead of 2-5 feet), but true blue-to-purple flowers that are just as big as those which adorn the statuesque standard plant. I successfully winter sowed B. australis var. minor using purchased seed. The seeds do require scarification, and are, consequently, a terrific choice for winter sowing; the method naturally loosens any hard seed coat. After you plant your seeds, you may wait a long time for germination and an even longer time (2-3 years or more, on a healthy plant) for flowers. Here's a tip: if planting a very tiny seedling, mark its location with a stake or rock so you don't lose track of it.
Once those beautiful blue flowers appear, they should return reliably every late spring-early summer. Baptisia is a long-lived perennial. The leaves mature to a silver grey and turn black after frost after which you may cut them back. You will find that your Baptisia dies down to (those long, tough, tap-) roots in the winter. Give it time and it will grow back all the way, bigger and sturdier than it was before. There's no need to fertilize False Indigo, and it is drought tolerant once established.
Suggestions: if you want to start with a plant, Baptisia tend to be carried by places which specialize in native plants, like Nearly Native Nursery. For seeds try Prairie Moon Nursery, JLHudson, Seedsman, Horizon Herbs or Specialty Perennials. Even more information can be found at Perennial ResourceTM.
Pictures appear courtesy of ©Perennial ResourceTM and hczone6.