Blue False Indigo: A True Beauty in Your Garden

Add some low maintenance perennials to your garden like Blue false indigo. Native to many areas of the U.S. it almost takes care of itself!

Blue false indigo flowers opening.
Blue false indigo opens its petals for pollinators.

In my side garden, two globe shaped masses of pretty blue green leaves catch my eye. Emerging from the top of each leafy globe, pale purple flowers climb thin green spears.

Two Blue false indigo plants, side by side in the middle of the garden bed, show off their blooms at almost the same time.

They are so striking between the maroon leaves of Diablo ninebark planted on either side. Stella D’Oro daylilies sit in front, sort of like a family portrait.

This picture is set against the green backdrop of Privet hedge in the garden bed seen by neighbors driving by. I hope the scene gives them a little joy.

Blue false indigo or Baptisia australis returns from the ground every spring as my side garden bed progresses from barren decomposing plant material to tulips and daffodils to leafy flowery globes like Blue false indigo.

The perennial belongs to a family of legumes like peas, soybeans, fava beans and peanuts. Plants like alfalfa, vetch and clover are legumes too.

Features

Native to: Eastern United States west to Nebraska and in Texas.

Name refers to:  False indigo is a U.S. native plant that looks similar to one cultivated by early settlers to dye cloth blue.  That plant, called Indigofera tentoria L. was grown in many parts of the world and is now considered invasive in many places.

The flowers of that plant are pink to lavender in color. The oval leaves grow opposite each other on the stem.  It’s the leaves that are processed to create the blue dye.

Blue false indigo may not work well for dye but it has other qualities. It’s a pretty native perennial. It fixes nitrogen in the soil for its own use.

Being a native plant adapted to the climate and soil, and providing its own food makes it easy to grow.

Unfortunately it is also considered threatened or endangered in several states, due to changes in its habitat.

Zones:  3-9

Trifoliate leaves of Blue false indigo.
Trifoliate leaves of Blue false indigo.

Leaves:  Blue green trifoliate, that is, one leaf is made up of three smaller leaflets. They turn silver grey in the fall.

Blooms:  May to June.  Depending on location, some species begin to bloom as early as April and as late as July. Besides blue purple, flowers come in white, yellow and red purple.

Four colorful petals fold over to form a ball. They open to reveal two more petals pressed together covering the stamen.

Pods form after flowers bloom.
Seed pods (left) form after pollinated flowers bloom.

If pollinated, a tiny seed pod much like a pea pod forms and grows to approximately 2.5 inches long. Inside the pods are kidney bean shaped seeds. After seed pods dry they rattle when shaken.

Height:  2.5 – 4 feet

Width:  3 – 4 feet

Grows from:  Seeds and rhizomes.  Make sure you choose the best location before you plant it because it does not like to be moved.

Of two plants that I relocated, one lived, the other died.  They have extensive rhizomes that grow deep as well as wide. It took a long time digging to find the end of the root system.

Allowing the seeds to fall to the ground once dried, will produce new plants the next year, sometimes in spots you don’t want them!

Spears of flowers on Blue false indigo.
Spears of blue purple flowers emerge from plant.

Care

  • Sunlight:  Full to part shade.
  • Soil:  Does best in average soil that is well drained. Tolerates poor, dry soil like clay or rocky types because it fixes nitrogen in its roots to supply itself with this nutrient.

Fixing nitrogen means that legumes like Blue false indigo get a little help from bacteria living in small nodules on the plants’ roots.

The bacteria take in nitrogen gas from the air and convert it to a form of nitrogen that the plant can use. In exchange, the bacteria gets sugar the plant created.

  • Water:  Average.
  • Fertilize: No need to fertilize.
  • Maintenance:  In fall when the leaves turn silver gray, the plant breaks off from the roots and falls over on the ground.

That’s a good time to get out the hedge shears and cut the dried branches into pieces to leave in the garden bed as a lightweight mulch. If left whole, the dried plant gets carried around the garden by the wind.

Problems/Pests

No serious problems. This is a beautiful, low maintenance plant.

Bumble bee pollinates Blue false indigo.
Bumble bees like the nectar.

Uses

Makes a low growing border in summer. Blue false indigo can be naturalized in native gardens. Just let the seed pods fall wherever and watch all the new plants come up the next year!

Attracts native bees and butterflies.  Deer don’t like it.

Enhance flower arrangements with seed pods still attached to their stems. Add them green in summer or let them dry on the plant and cut for fall designs.

As a native plant, Blue false indigo is easy to grow because it thrives in the climate and soil conditions of its home. A real plus for a beautiful plant in the garden.

References

Lady Bird Johnson Wildflower Center

Missouri Botanical Garden

Mt. Cuba Center

USDA Natural Resources Conservation Service

Copyright Juli Seyfried 2020

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juli

Juli is a writer and serious gardener. She gardens a small yard in an older suburban neighborhood. Lots of problem-solving and fun on a small property. Always something new to try!

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