Complete Guide to Blue False Indigo (Baptisia Australis)

If you’re interested in a flower that blooms in late Spring when most other plants aren’t blooming, one that doesn’t need fertilizer or watering….Oh, and how about if it has some of the most beautiful foliage of all?  Well then, say hello to Blue False Indigo (Scientific Name, Baptisia Austalis).

I’ve been growing this lovely flower for over 5 years and truly love it. The display that it puts on is truly ‘head-turning’. I’ve grown dozens of these plants and have learned a thing or two, and I can share what I’ve learned with you. This will be a complete profile on this flower.

In this article:

• What is Blue False Indigo?
• What are the benefits of Blue False Indigo
• How to Grow and Care for Blue False Indigo
  • How to Grow Blue False Indigo from seed
• Identification / Characteristics
• What Wildlife, Pests, and Diseases effect Blue False Indigo
• Where to buy Blue False Indigo
• Varieties of Blue False Indigo
• Uses of Blue False Indigo

What is Blue False Indigo?

Blue False Indigo is a large, showy perennial flower native to North America. Scientifically known as Baptisia Australis, it will grow beautiful blue to purple pea-like flowers in Spring and have lovely smooth blue-green foliage all year. Growing to a mature height of 4′ tall and wide, it attracts bees and hosts several butterflies. [1]

Although it is herbaceous and dies back every Winter, Blue False Indigo is long-lived and puts up multiple shoots to give it a shrub-like appearance. Slow to develop from seed, it is worth the wait as it makes for a head-turning display of blue, purple, or lavender flowers. It also has one of the deepest tap-roots native to North America, making Blue False Indigo very drought tolerant.

Blue False Indigo Facts

• The smooth blue-green foliage is attractive throughout the growing season
• A member of the pea family, Blue False Indigo is a legume and is nitrogen fixing and thus never requires fertilizer
• The common name, ‘Blue False Indigo’ is in reference to it being used as a dye by Native Americans and Colonists in place of true ‘Indigo’.[2]
• It is valuable to wildlife, as it hosts over 5 species of butterfly, skipper, and moths
• Toxic to humans and mammals alike, once full grown deer avoid this plant

Native Range of Blue False Indigo

Blue False Indigo is most common in Oklahoma, Kansas, and Southwest Missouri. The native range of Blue False Indigo funs from Texas, North to Nebraska/Iowa, then East to Pennsylvania, and finally South to North Carolina, Georgia, and Alabama.

Reference Table

Scientific Name	Baptisia Australis
Common Name(s)	False Indigo, Blue False Indigo, Wild Blue Indigo, Blue Wild Indigo
Native Range, USDA Zone	Middle & Eastern United States, zone 3-10
Bloom Time	Spring
Bloom Duration, Color	2 weeks, purple/blue
Height	3-5′
Spacing / Spread	3-4′
Light Requirements	full sun, partial sun
Soil Types	sandy loam, loam, clay, rocky soil
Moisture	medium/dry
Fauna Associations / Larval Hosts	Butterflies, bees. / Hosts several butterflies.

What are the Benefits of Blue False Indigo

Gorgeous flowers

A mature Blue False Indigo plant will put on one heck of a floral display in Spring. My oldest plant produces nearly 50 stalks. The top 12-18″ of each of these 50 stalks is covered in showy blue-purple flowers. It is absolutely stunning.

Beautiful foliage

The leaves of Blue False Indigo are very unique. The trifolate leaves feel very smooth to touch and look good all season. In general, insects don’t bother this plant either so the foliage will stay beautiful.

Wildlife

Blooming in mid-Spring, I’ve observed Blue False Indigo to be particularly popular with bees. Namely bumblebees. I frequently get to see various bumblebees digging to the flower to retrieve nectar, their little bumblebee-butts covered in pollen!

In addition to bees visiting for pollen, Blue False Indigo also hosts several species. In fact I was stung by one of them! The dangerous Saddleback Caterpillar will feed on the foliage. But don’t fret, that species of caterpillar is hosted by tons of flowers and trees, and is quite rare. Nonetheless I was lucky enough to get stun chasing a baseball one summer day!

Drought Tolerant

The roots on this plant go deep….really deep. That makes it extremely drought tolerant enabling it to grow on slopes and other places where many plants cannot.

Grow and Care for Blue False Indigo

Sunlight Requirements

Blue False Indigo prefers full sun, which is six or more hours of direct sunlight per day. It can tolerate partial shade, which is 4-6 hours of sun, but the plant will not be as large or showy. [3]

Soil Requirements

Blue False Indigo is very adaptable when it comes to soil texture. It can grow in rocky soil, sandy loam, clay – as long as the soil can drain it should grow just fine.

Moisture Requirements

For moisture, Blue False Indigo prefers average moisture to dry conditions.

Problems

The biggest problem you will face with Blue False Indigo is the plant flopping over. At about year 4 or 5, they will be very prone to leaning over in one large mass due to storms or high winds. This usually happens within a month after blooming. If it stays together and ‘flops’, then it doesn’t look as bad. But it would be nice if they would just stay erect.

You have several options to keep Blue False Indigo looking good when it flops over.

• You can plant it in crowded conditions, where it won’t be as able to ‘flop’. This has an added benefit of more competition for roots, which seems to help keep plants upright.
• Staking Blue False Indigo in a ‘circular fashion’ can help keep the stalks upright as well. But you need to do this before the plant begins to flop. Just place some stakes very close to the stalks, and tie a few layers of twine around the stakes.

Fertilizer

As a legume, Blue False Indigo will not require fertilizer. It’s roots are nitrogen fixing from the air, which basically means that it will gather and store it’s own fertilizer in it’s roots for use throughout the growing season.

Identification and Characteristics of Blue False Indigo

Stalk

Blue False Indigo produce numerous shoots in early Spring that look like asparagus. As they mature, it will form an upright/erect shrubby appearance, however this plant will die back to the ground each Autumn. The stems are rounds and smooth, and quite stout, light green in appearance.

Leaf

Leaves of Blue False indigo are alternate along the stalk and will run the entire length of the stem with short stems (1/2″ petioles). The stemless leaflets are oblong-lanceolate in shape, and have smooth edges (margins). They will be green to blue-green in color, and very attractive until Autumn, when they will turn black.

Flower

Along the upper stems are 6″-18″ long racemes of flowers that are pea-like, and dark blue to light-purple in color. Individual flowers are approximately 1″ long, with 5 petals and a tubular calyx. The individual flowers are attached to the raceme (stalk) with short 1/2″ stem (pedicel).

Flowering is 2-4 weeks in mid-Spring, and quite showy. A mature specimen really puts on a display.

After flowering, large seed pods form where the flowers once were. These pods are 2-3″ long by 1″ wide, and somewhat oblong in shape. They are initially green, turning black by late Summer.

How to save seeds from Blue False Indigo

To save seed, wait until the pods turn black. Then, go shake a stalk and listen for seeds rattling within the pods. If you hear the seeds rattling, you know the seed is ripe.

Collect pods and place in a brown paper bag. Store the bag in a cool dry place for a week, then open the pods and remove the seed. There should be minimal chaff in this operation.

Root system

Blue False Indigo has a tap root that runs very deep. This plant is very drought tolerant.

Blue False Indigo Toxicity

Blue False Indigo is toxic, containing an alkaloid Cytisine with nicotinic receptors. If ingested, in can cause blurred vision, vomiting, vertigo, and inability to stand.[toxic] The University of North Carolina lists Baptisia as a ‘low toxic plant’ [4], but none the less you should not consume any part of this plant.

A case study from 2015 found two patients who ate 5-6 stalks of what they thought was ‘wild asparagus’ they had picked at a local storm water garden were severely poisoned. Within 15-30 minutes of eating the Baptisia they had the onset of vomiting, nausea, blurred vision, and vertigo. [5] This is understandable, as the image above shows there is a resemblance to Asparagus stalks emerging in Spring.

Dogs and cats

You should keep your pets away from Baptisia, as alkaloids present in the foliage are likely toxic to your dogs. It is likely that they would avoid these plants anyway, as deer avoid them due to the bitter taste. But to be on the safe side, keep your dogs and cats away from all Baptisia species.

How to Grow Blue False Indigo from Seed

It is very easy to germinate Blue False Indigo seeds, but they do require scarification. The seeds have a hard outer shell, and we need to remove part of it with sandpaper or a file before planting. I’ve germinated this seed many times, and sandpaper is my preferred method.

Note – there are some references/sources that state these seeds need 10-30 days of cold stratification. I’ve never found this to be the case. I always germinate my seeds in Spring, when my Winter-Sown seeds start to germinate.

To scarify Blue False Indigo seed, carefully rub the seed on sandpaper (I use 150 grit) several times, or rub a file across the seed a few times until you can see white. Once you see a white spot, this indicates you have gotten through the shell. Do not over scarify a seed and keep rubbing it, as you may kill the seed.

Plant Blue False Indigo seeds 1/2″ deep (12 mm) in a container with moist potting soil. Place the container in a location that receives morning sun and afternoon shade.

If you scarified the seed properly, and kept it moist you should seed germination within 5-14 days. Typically I see the seed germinate within 5 days.

How long to establish from seed

Blue False Indigo grows slowly as it develops it’s extensive taproot system. The first year you can expect a single stalk. By year two, you should have 6-10 small stalks. And by year three, you can expect blooms.

But it usually won’t reach it’s full size until year four or five. So, be patient, but it is worth the wait. The image below is a progression of one of my plants from years 3-5, with year five being ‘full’ size.

Growing Blue False Indigo from Cuttings

To make cuttings of Blue False Indigo, cut a stalk at about 6” long in early Spring, and cut it at an angle.  Dip it in a rooting compound, and place into a sand/compost mixture, under a plastic dome and keep moist.  After several weeks, check if roots have developed.  If so, you can plant into a pot to mature further, or out into the garden.  Do not let the stalk dry out.

Wildlife, Pests, and Diseases associated with Blue False Indigo

Pollinators

Bumblebees are the primarily pollinators of Blue False Indigo, and you will see them frequenting the flowers in Spring. Often you will notice they have to really work to reach the nectar, exposing their Bombus derriere full of pollen!

But Blue False Indigo also hosts several species of butterfly, moth, and skipper including the Wild Indigo Duskywing, Hoary Edge, Frosted Elfin, Orange Sulfur, and Marine Blue. [7] [8]

Pests

In addition to moth/butterfly larvae, there are several beetles who feed on the leaves, and whose larvae will also feed on the seeds. Also, the Ash-Gray Blister Beetle feeds on the flowers and developing seed pods. [7] [8]

I’ve never found extensive damage from any insect on these plants. I rarely notice any damage at all to be honest. Based on my personal experience, you shouldn’t have to worry about the foliage becoming unsightly due to insects or anything else. The limited damage that may occur from native insects is all part of the ecosystem.

Deer and Rabbits

Most references will tell you that deer and rabbits don’t like Blue False Indigo.  I’ve found this to be true for mature plants.  However, young tender seedlings and new growth when emerging from the ground can get damaged.  I’ve found rabbits in particular to enjoy eating young seedlings of Blue False Indigo I’ve set out into the garden. 

For younger plants, I strongly recommend you protect them with Liquid Fence. It truly works, and I use it on all my at-risk plants. You can find a link to it in our recommended products page.

Disease

If blue false indigo is grown in high humid, shady, or compact area with poor airflow then fungus can develop.  I always place my plants in areas with plenty of airflow and sun, as that is Blue False Indigo’s preferred growing conditions. And I’ve never seen any form of fungus or powdery mildew on my plants.

Varieties of Blue False Indigo

Like many popular landscaping plants, many cultivars of Blue False Indigo have been bred. But there are also some true native verities as well. True native varieties will produce seed that is ‘true to type’, and make more of the same plant with the same characteristics.

Native varieties of Blue False Indigo

• Baptisia australis var. aberrans – grows in the Southeastern range of the distribution. Is adapted to dry limestone soil and uplands.
• Baptisia australis var. australis – Is native to the regions east of the Mississippi river. The most common vairiety.
• Baptisia australis var. minor – This covers the western range of the plant. It is smaller, 18-24″ tall and wide. The flowers are still the same size as the larger plants, and are fragrant too. (I’ll be growing this variety this year)

Cultivars of Blue False Indigo

The Chicago Botanic Garden has instituted an aggressive breeding program for all species of Baptisia to invent new varieties. [9] Their research has found numerous complex hybridization schemes are possible. Unfortunately, it is not currently known if these different flower colors interfere with pollinators being able to locate the plants.

But, none the less I present you with a sampling of the cultivars they have created.

• Blueberry Sunday is a cultivar developed for a compact size. The Mount Cuba Center in their exhaustive research found this to be the best variety due to it’s size, inflorescence, and it’s resistance to flopping over. [10]
• Purple Smoke is a cross between Baptisia australis var. aberrans and Baptisia alba (White False Indigo). The flowers are purple, but appear to have been dusted white. It has a long bloom duration of 5 weeks.
• Starlite Prarieblues is a cross between B. australis and Baptisia bracteata. The flower buds are purple, but when open reveal light blue flowers with yellow ‘noses’. This variety blooms for 5 weeks, which is 1-2 weeks longer than the straight species.
• Twilite Prairieblues is a hybrid bred from Baptisia australis and Baptisia sphaerocarpa. This cross produces dark purple flowers with yellow keels. The flower spikes are extra prominent on this variety.
• Baptisia Solar Flare is a complex hybrid between B. alba, Baptisia tinctoria, and Baptisia australis. Flowers start as a yellow color and change to purple as the flowers age.

Where you can buy Blue False Indigo

Blue False Indigo is available from smaller nurseries, but always at limited quantities (due to the time it takes to grow from seed). But it can be purchased at specialty nurseries that deal in Native Plants. You can find native plant nurseries near you on our interactive map. Just don’t wait around because quantities are always limited – locate nurseries in Spring, and call them to ask if they have Baptisia.

Where to buy seeds

We have ordered a variety of native flower seeds from Everwilde Farms, which you can order right from Amazon through our link on our RECOMMENDED PRODUCTS PAGE. (We may earn a small commission when you purchase through our links, at no cost to you. This helps support our website.)

Uses of Blue False Indigo

Garden Uses

Blue False Indigo is very versatile in the garden. The large size can make a great focal point in an island flower bed, or the back of a flower bed against a house. It also does great in meadows, border gardens, or micro-prairies. The biggest challenge will be to keep the plant upright, or grouped if it does flop.

The key things to remember is that you should try to plant it where it can get sun from all directions. This helps the plant grow vertical. Additionally, try to get other plants to grow close to it for offering support as well as providing more root competition.

Companion Plants

There are many species of flower that enjoy similar growing conditions as Blue False Indigo. Some flowers that would bloom concurrently or overlapping include the following;

• Lanceleaf Coreopsis
• Pale Purple Coneflower
• Echinacea Tennesse
• Columbine
• Virginia Bluebells
• Hairy Beardtongue
• Foxglove Beardtongue

If you wanted to make sure you had color for most of the season, some flowers that would bloom after Blue False Indigo include:

• Purple Coneflower
• Aromatic Aster
• Black Eyed Susan
• Spotted Beebalm
• Wild Bergamot
• Prairie Blazing Star

Medicinal Uses

The Cherokee tribe used Blue False Indigo medicinally several different ways. [11] A old fusion was used for vomiting, used as a purgative, and emetic. A poultice was used to reduce inflammation and stop mortification as a gynecological aid. And finally, a hot infusion of root was used to relieve the symptoms of toothaches. [12]

Now, based on what you read previously in the section on Toxicity, it makes sense that the Native Americans also found that ingesting this plant induced vomiting. It’s toxic!

Used as a dye

The Cherokee and early Colonial settlers also used the flowers to make a blue dye for fabric. [13] It was not as ‘vivid’ as dye made from true Indigo plants. But, it served it’s purpose well, and was readily available in the Spring.

Find more native plants here