Plant of the Month: Yellow Wild Indigo

Presented by Diane Humes
April 9, 2018

Botanical name: Baptisia sphaerocarpa
Common names: Yellow Wild Indigo, Yellow Bush Pea, Yellow Wisteria, Green Wild Indigo, Bush Pea
Family Fabaceae (Pea)

April’s plant of the month is Yellow Wild Indigo, or Baptisia sphaerocarpa. It is currently blooming all over Armand Bayou Nature Center and in most fields where you see these mounds of yellow flowers. You can see it has a rounded form.

Baptisia is derived from the Greek word bapto, which means “to dye.” Early settlers used this plant as a dye because they couldn’t afford real indigo, but this was a reasonable substitute, so they used it to get blue dye.

The species name sphaerocarpa comes from the Greek words sphaero (sphere) and carpa (fruiting body), meaning “rounded fruit.” That’s our plant of the month.

It grows in the south. You can see that it’s found in Texas, Louisiana, Oklahoma, Arkansas, Mississippi, and Missouri, although the Missouri Botanical Garden questioned whether it was actually native because they thought it had been introduced in several places and then spread. Maybe yes, maybe no. This information is from the USDA Plants Database.

This is what it looks like. This is why I give you the code. When you search for it, if you spell the name wrong, it will say, “huh, there’s no such plant.” If you get the wrong common name, it will say the same thing. So, BASP, the two first initials for Baptisia and SP for sphaerocarpa, will help you find the plant. In addition to Yellow Wild Indigo, common names include Yellow Bush Pea, Yellow Wisteria, Green Wild Indigo, and Bush Pea. It’s in the pea family.

Here’s what it’s about. The upper picture shows what it looks like as a young plant, and there’s a close-up of the flowers. It’s a perennial, warm-season legume. It’s herbaceous and gets to be about 2 to 4 feet high and about 2 to 4 feet wide, so it can be a pretty good-sized bush. It thrives in open areas with full sun and develops really deep root systems, which is beneficial for a prairie.

The leaves are bluish-green, alternate, and divided palmately into three leaflets. Flowers are bright yellow, about an inch long, blooming now from April to May. The seed pods are round, about three-quarters of an inch in diameter, and they are brown. There’s another species (B. beacteata) where the pods are black, which helps distinguish them.

It’s drought-tolerant, and the seed pods look like this on the plant after the flowers have gone away. It’s not too picky about soil. Our zone hardiness is 5 to 8. I’m not sure how well it self-seeds, but I’m guessing it does. Sooner or later, those seeds do open up and spread. This is what it looks like with the seed pod open, showing little seeds inside.

It’s a good wildlife plant, serving as a nectar source for bumblebees and carpenter bees, and as a host plant for several butterflies. One source mentioned that songbirds eat the seeds, but they would have to get the pods open first as they are pretty stout.

It’s a member of the pea family, Fabaceae. The Latin word for beans is fava, and there was a species named Fava, but the name changed while the family name stuck. So, it’s the Fabaceae or the Leguminosae, which is an older name. This family includes soybeans, beans, chickpeas, alfalfa, peanuts, carob, and some weedy species like broom, black locust, gorse, and kudzu. It’s the third-largest plant family in the world.

So, that’s what there is to say about Yellow Bush Pea.

Thank you very much.