Blue Indigo

Light Needs

Partial Sun to Full Sun

(At Least 5 Hours of Direct Sunlight)

Mature Height

3-4 Feet

Mature Spread

3-4 Feet

Growing Zones

3 to 8

Native and easy to grow, Blue Indigo (Baptisia australis) also boasts pretty bluish purple flowers. Although this perennial dies back to the ground each year (don’t be alarmed), it re-emerges in spring and grows back to a robust 3 to 4 feet high and wide, resembling a shrub more than a perennial. The leaves are a smooth green, and in late spring to early summer, their stems support a string of flowers at the end.

Also drought tolerant, this baptisia is a great choice for rock gardens or deep containers. Its color lasts long, from the time it begins to grow each spring until the first frost. Hardy in zones 3 through 8, the plant can handle some hot sun but survive cold winters underground. They’re also disease- and pest-free plant choices. The pretty foliage really shines as a backdrop for shorter perennials that bloom later. 

Blue Indigo Care

The plant does not need fertile soil to grow, so select any area that gets lots of sun (at least 6 hours a day). The soil should drain well, however. Be sure to plant it at the same level as in its current container to avoid placing it too deeply in the ground. The only fertilizer you need is a top-dressing of compost or a balanced slow-release fertilizer once in spring as new growth appears. 

As flowers fade, you can leave them to enjoy the seed pods they form (these are relatives of peas) or pinch them off. After your Blue Indigo has finished flowering, prune back about one-third of the plant to give it a more attractive shape. Also remove any yellow or dead leaves. As soon as the first fall frost hits, the leaves turn black and die back. But the plant should appear from the soil again in spring. 

Blue Indigo Spacing

Blue Indigo starts out as tiny, upright growth, but it can reach nearly 4 feet high and around by the end of summer. Be sure to space the plants at least 3 feet apart.