Baptisia australis      False blue indigo


An underused cut flower, whose limitation appears to be a long maturity period and perhaps a limited availability of plants; however, seed can easily be germinated and flowers are well received by the consumer.  The genus sports flowers in many colors, mainly in purple, white, and yellow, as well as a couple of hybrids in rather unusual colors.  Although flowers are most noticeable, the foliage and the pods can also be harvested successfully.
    

The genus, which contains about 35 species, is rife with folklore. The genus comes from the Greek word bapto (“to dip”), a reference to the flower extract’s once being used as a substitute for indigo. Baptisia australis was often used for blue dyes, while B. tinctoria was a source of yellow dye in the southern United States.  Baptisia is one of the most rewarding and historically fascinating genera available to growers and landscapers alike.  Native to large areas of the United States, plants afford exceptional performance and a mini-lesson in early American history.  The common name refers to its use as a substitute, albeit not a great substitute, for the true indigo, Indigofera, of the West Indies. When Indigofera was in short supply, the English government contracted with farmers in Georgia and South Carolina in the mid 1700s to “farm” false blue indigo, B. australis, to increase the supply of the dye.
    

The farming of baptisia was one of the first recorded examples of agricultural subsidies. The process used to extract the dye was incredibly cumbersome and time-consuming.  A report in the Georgia State Gazette of 10 May 1788 provided directions “for the Cultivation and Manufacture of Indigo” by “an Indigo Planter.” What with planting, cutting, beating, draining, and pressing, the process was doomed to a short life. Today, baptisia provides growers with a living example of Americana and, more importantly, with useful, beautiful cut flowers.

Propagation

It is best to gather seeds from existing plants, although seeds may be purchased. The key to successful seed harvest is to gather the seed as the seed pods turn black and sow when fresh. Seed propagation is less erratic when seeds are given a scarification treatment. Piercing or scraping the seeds with sandpaper or another abrasive substance is helpful, but not essential. This allows moisture and oxygen to penetrate the seed coat. Acid scarification is used commercially but should be performed only by trained individuals. Once the seeds have been treated, place them in a peat/vermiculite mix in a moist, warm environment.

Germination of over 90% occurred regardless of acid and mechanical scarification, cold and hot water soaking, or cold stratification. A cold treatment of approximately 40F is also useful and can be accomplished in a cold frame, refrigerator or incubator. Seed germinates in 10-18 days at 70F.  The fleshy roots may also be divided between October and March.

Growing-on

Transplant plugs or seedlings to 4-5” containers and grow on at 58F  until they are large enough to be placed in the field. Once in the field, they should not be disturbed.

Environmental Factors

Temperature: Cold is beneficial for growth and flowering but plants are tolerant of warm summer weather.  Plants are perennials and flower for many years.
Photoperiod: Plants do not appear to have a photoperiodic requirement.

Field Performance

Yield: Little information on yield is available, but nothing should be harvested the first year, and minimal harvesting should be done the second. By the fourth year, plants are fully mature, and a dozen stems per plant can be harvested.
Spacing. We recommend spacing of at least 2’ between plants to allow them to fill in. Plants will be productive for many years, so dense spacing is counterproductive.
Fertilization: Plants belong to the pea family, so they are able to produce their own nitrogen; however, this does not mean that plants do not need feeding.  Side dress with a complete fertilizer as new shoots arise. No additional fertilizing is needed after early summer.
Longevity: If plants are properly cared for, production for 10 years is not unusual.

Stage of Harvest

Flowers are harvested when approximately one-third of the flowers on the inflorescence are open. Janet Foss of Chehalis, Washington, cuts her fresh blooms when just a few flowers are open (not more than one-third) but all the buds are colored. She has problems with shattering if they’re left too long in the field. In Vermont, Ed Pincus cuts 2-3’ main stems and then obtains additional side branches which he can cut or leave to develop the green pods. The pods eventually turn black. Either way, he notes, the foliage and the pods are quite attractive.

Pods start green and eventually turn black. Pods remain green longer in the South and on the West Coast because cool weather is slower to arrive. Not all inflorescences produce pods, so do not expect the same yield of fruit as flowers.  Pods can be harvested when they are green, but better contrast between leaves and fruit occurs if they are brown to black. Waiting too long is not recommended, however, if the foliage is an important part of the “podded” seem. The foliage turns black in the fall and declines rapidly, at which time, put your falsies to bed.

Postharvest

Growers who cut into a hydrating solution report postharvest life of 7-10 days. Warm water in the bucket is particularly recommended for baptisia.

Cultivars

No cultivars of Baptisia australis are available; however, several hybrids have been released.

‘Carolina Moonlight’, a cross between B. sphaerocephala and B. alba is said to produce forty to fifty 18” spikes of buttery yellow flowers per plant.

‘Purple Smoke’ is a hybrid between Baptisia australis and B. alba, a white-flowered species, released by the North Carolina Botanical Garden in Chapel Hill. The smoky-blue flowers are held in upright inflorescences on 3’ (90 cm) tall plants with gray stems.  Mature plants may produce 50 stems.

‘Solar Flare Prairie Blues’, also from the Chicago Botanic Gardens, is considered a vigorous flowerer.

‘Twilite Prairie Blues’, introduced by Jim Ault at the Chicago Botanic Gardens, bears deep violet-purple flowers on 32” long.  As many as 100 stems per plant have been reported.

Additional Species

Baptisia alba (white baptisia) is an exceptional species, laden with white flowers on black stems. Plants are more shade tolerant than B. australis, and earlier to flower. ‘Pendula’ is similar in flower but with pendulous seed pods. The nomenclature of the genus is mixed up, other white-flowered forms include B. lactea and B. leucantha.

Baptisia sphaerocarpa (yellow baptisia) has golden-yellow flowers on 2½-3’ tall plants. Native to Arkansas and Oklahoma, plants are excellent choices for the western states.  Tony Avent reports that his 2’ tall, 4” wide plant has displayed over 130 flower spikes at once and the spikes are 12-15” tall.  The many blooms give way to round seed pods rather than elongated pods.

Pests and Diseases

Leaf spots, powdery mildew (Erysiphe, Microsphaera), rust (Puccinia), and root rots are not uncommon.

Foliar nematodes (Aphelenchoides spp.) cause discolored spots on foliage that can worsen to leaf blight later in the season.

Grower Comments

“I have a patch of baptisia that is 6 years old. The original plugs were purchased and planted in our field before we had a well. I had heard it was drought tolerant and sure enough, it established itself and flourished without a lot of TLC.” Maureen Charde, High Meadow Flower Farm, Warwick, New York.

“I have grown Baptisia australis for 4 years, and I think it is a real winner. Not only can I sell the flower, but the foliage and seed pods are wonderful too. The plants ‘last forever,’ like peonies, and are natives in North America.” Pat Bowman, Cape May Cut Flowers, Cape May, New Jersey.

“I don’t think this is typical but in ’06 I cut 970 stems and in ’07 870 stems from approximately 225 plants. I think my production is low as baptisia is a slow grower in these parts.”  Tom Wikstrom, Happy Trowels Farm, Ogden, Utah.

“When baptisa is happy you can get over 20 stems a plant, if not, you might get none.  I like the bright blue flowers.  Personally they are not my favorite; what I really love are the seed pods, but the production is so low it has not been worth it for me for only                  2-5 stems per plant.” Janet Foss, J. Foss Garden, Chehalis, Washington.

“My older plants (six years) yield about 25 stems per plant and will continue to produce new ones if I do not let them go to seed because it is so cool here most of the summer.  My young plants have only about 5 or 6 but it increases every year.”   Thea Folls, Folls Flower Farm, Auburn, New York.

“We get about 10-12 stems per plant on the australis that has been in the ground for six years. We never cut more than a third of the plant. The ‘Purple Smoke’ is about the same.  ‘Carolina Moonlight’ and ‘Screaming Yellow’ don’t have quite as many stems yet but have been in the ground for only three years.  The white produces the least amount for us right now simply because it has not had the most ideal conditions.  We do also cut for foliage and fresh pods. The foliage and fresh pods should be cut only when the plants are very well hydrated.  The foliage should not be used in corsages as it will not hold without hydration, we have proven this.”  Sybil and Gary Calder, Sunrise to Sunset Gardens,                 Clayton, South Carolin