The Perennial Matchmaker

Baptisias (Baptisia), also known as false indigos or wild indigos, are a blessing for gardeners who appreciate easy-care plants. But these adaptable perennials are more than just sturdy and long lived: Their spiky bloom clusters are very striking in late-spring or early-summer combinations.

Blue false indigo (B. australis), with blue to purple-blue flowers and bluish green leaves, is one of the most widely grown species. It typically grows 3 to 5 feet tall and wide and is hardy in Zones 3 to 9. White false indigo (usually sold as B. alba), suited to Zones 4 to 9, is similar in size but more open in habit, with dusky gray stems and white flowers.

Yellow false indigo (B. sphaerocarpa), with bright yellow flowers and light green leaves, tends to be more compact at 2 to 3 feet tall and wide, though it may reach a foot or so taller. It’s hardy in Zones 4 or 5 to 9.

There are many stunning hybrids of these and other species, such as light yellow ‘Carolina Moonlight’, soft purple ‘Purple Smoke’, and Twilite Prairieblues (‘Twilite’), with violet, purple-blue, and yellow in each bloom. Most reach 3 to 4 feet tall in bloom and are adapted to Zones 4 to 9.

Baptisias that bloom in the blue to purple range complement a number of similarly colored perennials that typically flower around the same time, including bellflowers (Campanula), catmints (Nepeta), and Siberian irises (Iris sibirica), to name a few. They (and the white and yellow baptisias, too) are outstanding with white-flowered partners, such as “Festiva Maxima” peopny (Paeonia lactiflora); bright to soft yellow flowers, like those of ‘Moonshine’ yarrow (Achillea) and yellow meadow rue (Thalictrum flavum subsp. glaucum); and delicate to warm pink blooms, like those of Lancaster geranium (Geranium sanguineum var. striatum) and red valerian (Centranthus ruber).

The blue and purple baptisias—particularly the darker ones, such as ‘Dutch Chocolate’—may blend into a dark background, so consider siting them against a lighter backdrop, such as a pale fence or wall or a yellow-leaved shrub, such as golden elderberry (Sambucus nigra ‘Aurea’).

Many of the hybrid baptisias include two or more colors in their flowers or change color as the blooms age. Pictures can give you some idea of what to expect, but if you want to take best advantage of them, you may wish to watch them through at least one bloom period to see how they look in your garden before choosing permanent companions. Consider using bearded or Dutch irises to pick up some of the more unusual colors and shading, such as purple-and-bronze ‘Lion King’ Dutch iris to echo the orangey touches in ‘Solar Flare’.

Once the flowering period is over, the foliage is the main color feature. Repeat the blue-green leaf color present on many baptisias with perennials that have a similar foliage color, such as ‘Dallas Blues’ switch grass (Panicum virgatum), dianthus (Dianthus), and yuccas (Yucca). Expand the palette a bit with gray to silver leaves, like those of artemisias (Artemisia), lamb’s ears (Stachys byzantina), and rattlesnake master (Eryngium yuccifolium), or go for more zip with solid yellow or brightly variegated foliage, like that of ‘Isla Gold’ tansy (Tanacetum vulgare) or ‘Nora Leigh’ summer phlox (Phlox paniculata).

A Perfect Match

Bearded irises make spectacular partners for baptisias in bloom, and there are thousands to choose from to create whatever sort of contrast or harmony you’d like. ‘Edith Wolford’ is my own favorite, because its blue-and-yellow flowers work equally well with solid blue or all-yellow baptisias.

Baptisia plants eventually form broad, domed mounds in leaf. It takes them several years to reach their full spread, though, so consider using annuals around them until they’re established; then you can place perennial partners where they won’t get smothered by the baptisias. The bottom third of the stems can be somewhat bare, so use lower, bushy companions, such as hardy geraniums (Geranium) or mountain bluet (Centaurea montana), in front of your baptisia clumps. For a contrast in form, use tall, vertical perennials, such as Culver’s root (Veronicastrum virginicum) or ‘Northwind’ switch grass (P. virgatum), behind them.

Plants with columnar flower clusters, such as delphiniums (Delphinium) and lupines (Lupinus), repeat the shape of the baptisias in bloom, while slender spikes, like those of perennial salvias (Salvia) and spike speedwell (Veronica spicata), echo the vertical look in a more refined form. For variety, pair the chunky spikes of in-bloom baptisias with equally bold globe- or bowl-shaped blooms, like those of ‘Mount Everest’ or ‘Purple Sensation’ alliums (Allium), Oriental poppy (Papaver orientale), or peonies. Baptisia blooms also contrast well with daisy-form or flat-clustered flowers, such as purple coneflower (Echinacea purpurea) or yarrows, and with airy or plumy flower heads, like those of columbine meadow rue (Thalictrum aquilegifolium) or giant fleeceflower (Persicaria polymorpha).

In the southern parts of their range, baptisias usually sprout in early spring and begin to bloom in mid-spring; in northern gardens, they emerge in mid- or late spring and flower in late spring to early summer. The gray to grayish purple stems of white false indigo and its hybrids are most noticeable early in the growing season. You might choose to echo them with similarly colored flowers or leaves, like those of ‘Blackberry Ice’ heuchera (Heuchera) or ‘Queen of Night’ tulip.

Once their flowers begin to open, baptisias are usually in bloom for 3 to 4 weeks. Cut them back by about half after flowering to keep the plants denser and bushier, or leave them alone to get the inflated or rounded seedpods for later interest. From early or midsummer to frost, the key features of baptisias are their handsome form and foliage.

Bloom Buddies

Marvelous Matches for Flowering Combos

Baptisias (Baptisia) thrive in full sun but can take light shade, and they’ll grow in either dry or moist soil (even in clayey soil, as long as the site isn’t constantly wet). That gives you lots of potential flowering companions to choose from, including those listed below.

Bearded irises (Iris Bearded Hybrids)

Bellflowers (Campanula)

Carolina phlox (Phlox carolina)

Columbines (Aquilegia)

Coral bells (Heuchera sanguinea)

Coreopsis (Coreopsis)

Dianthus (Dianthus)

Echinaceas (Echinacea)

Gas plant (Dictamnus albus)

Meadow phlox (Phlox maculata)

Oriental poppy (Papaver orientale)

Penstemons (Penstemon)

Peonies (Paeonia)

Pincushion flowers (Scabiosa)

Red valerian (Centranthus ruber)

Siberian iris (Iris sibirica)

Sweet iris (Iris pallida)

Yarrows (Achillea)