The Perfect Purple Pea Plant

Baptisia australis_Flase Indigo_HAS-CoSpgsCO_LAH_0247I fell in love with Baptisia australis (aka Blue False Indigo) the first time I saw it in full bloom at the Denver Botanic Gardens. Then again, I do have a “thing” for purple flowers (which probably explains the profusion of cat mint, May Queen sage, and Veronica growing in front of our house).

Baptisia is a perennial; the plants die back to the roots after the first freeze. However, come spring the plants quickly grow into attractive mounded shrubs about three to four feet in diameter. If that is too large for your space, there’s a dwarf form that only reaches half that size.

Baptisia alba macrophylla_White Wild Indigo_DBG_LAH_1436In May (here in Colorado) their clover-like foliage is covered with huge spikes of large, pea-shaped flowers. While Baptisia australis is described as “indigo blue” (that means “gorgeous purple” in horticulture-ese); other Baptisia species have white or yellow flowers. All are native to the eastern half of the United States. Butterflies are attracted to the blossoms.

After bloom, the flowers give way to long, flat, black seed pods. These are decorative enough to be left to dry on the plant, then cut for indoor arrangements. If you shake them, you can hear the seeds rattling around inside. (You can sow the seeds as well; new plants take two to three years to reach blooming size.)

Baptisia australis_False Indigo_DBG-CO_LAH_6470They might appear somewhat delicate, but the Baptisias are tough cookies. They must be tough if they manage to flourish under conditions as diverse as are found in South Carolina and Colorado Springs! Clemson University’s Cooperative Extension website describes them as “deer resistant, heat and humidity tolerant, and drought tolerant once established” and the Missouri Botanical Garden says they tolerate rabbits, drought, erosion, clay soil, dry soil, and shallow-rocky soil. That pretty much covers it—although I notice that no one mentions hail.

Situate plants in full sun to part shade, water to establish, then keep them on the medium-dry side. While they get a bit bigger over time, they do not need dividing, and in fact do best if left undisturbed for years.

Not surprisingly, Baptisia fits perfectly into natural settings; it’s well suited for cottage gardens or perennial borders as well. Try combining them with other perennials with similar needs, such as Jupiter’s Beard (Centranthus ruber), perhaps mixed with an Artemisia for its silvery foliage. Or, go for contrast with soft yellow Coreopsis ‘Moonbeam.’ Baptisia looks best planted in small groups.

Is Baptisia a perfect plant for Colorado? I found one problem, and it’s only an issue if you have small children in your garden—all parts of the plant are poisonous.

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