How to Grow and Care for False Indigo (Wild Indigo)

How to Plant False Indigo (Wild Indigo)

When to Plant

False indigo is best planted as nursery starts in the spring after frosty conditions have passed or in the early fall in warmer climates.

If planting seeds in spring, ensure they have been cold-stratified to spur sprouting. If planted by seed in the fall, the cold weather triggers germination and growth in the spring.

Where to Plant

False indigo prefers a full-sun location to prevent it from becoming leggy or scraggly, and the sunlight will keep away fungal growth. False or wild indigo can grow in most soil types, tolerating a range of pH, and in poor or rich soil.

It does not do well as an indoor plant. It can grow in containers but is not the best candidate for it. False indigo requires a deep container for its long taproot. Its long taproot also restricts it from being disturbed for repotting.

Spacing, Depth, and Support

Plant a nursery specimen starting at a depth no deeper than the height of the pot or container it came in. If planting seeds, sow them about 14 inch deep, lightly covering them with soil. Space them approximately 2 to 3 inches apart to allow for growth.

Plants can sometimes flop outward from the center of the clump, especially if grown in shady conditions that cause them to get leggy. If the plant gets leggy, giving it a large hoop support can help keep it upright.

False Indigo (Wild Indigo) Care

Here are the main care requirements for growing a false indigo:

• Plant false indigo in full sun to prevent legginess.
• Give support, such as a hoop, if the plant gets floppy.
• Prefers well-draining soil but tolerates somewhat dry soil once established.
• Tolerates most pH environments but prefers slightly acidic to neutral.
• Needs water regularly, one inch per week, in the first year; afterward, becomes drought tolerant.
• Spreads slowly on its own through self-seeding.

Light Requirements

False Indigo will get floppy without at least six hours of sunlight daily. Full sun also prevents fungal diseases.

Soil

False indigo prefers moderately well-draining soils but tolerates dry soils once well-established. It is not particular about soil pH but does best in slightly acidic soil to neutral (5.0-6.8).

Water

Keep false indigo watered regularly for the first year, but after this, it will get by with about 1 inch of water every couple of weeks. Once established, Baptisia is relatively drought-tolerant. This is a native wildflower, and in most regions, it does fine with whatever rainfall nature provides.

Temperature and Humidity

False indigo will thrive in the garden in the conditions throughout its hardiness range, zones 3 to 9. It does equally well in dry and humid climates, provided it gets adequate soil moisture.

Fertilizer

Feeding is unnecessary for these plants and can even be counterproductive; excessive fertilizing can cause the plant to get leggy and flop over.

Types of False Indigo (Wild Indigo)

The pure species Baptisia australis stands out because of its striking blue flowers. Newer hybrid forms of Baptisia have yellow and purple flowers.

• • ‘Purple Smoke’: This is a hybrid of B. australis var. aberrans and B. alba. It has purple eyes in the center of blue flowers.
  • ‘Carolina Moonlight’: This cross between B. sphaerocarpa and B. alba has butter-yellow flowers on 18-inch-long spikes that bloom for up to six weeks. The plants are 3 feet tall by 3 feet wide.
  • ‘Twilite Prairieblues’: This hybrid, one of several in the Prairieblue series developed by the Chicago Botanical Garden, is a cross between B. australis and B. sphaerocarpa. Its flowers are bicolor, purple with buttery yellow. The plants are 3 feet tall and wide.
  • Twilite Prairieblues: This bicolor hybrid is another cross between B. australis and B. sphaerocarpa. It has deep violet-purple flowers with yellow highlights. Plants grow 3 to 5 feet tall and 4 to 5 feet wide.
  • Midnight Prairieblues: This is a complex hybrid of B. tinctoria, B. alba, and probably B. australis. Its flower spikes are extremely long (24 inches) and deep blue-violet. Mature plants grow 4 to 5 feet tall by 3 12 by 4 feet wide.
  • Solar Flare Prairieblues: This is another complicated hybrid, probably derived from B. alba, B. tinctoria, and B. australis. As the flowers age, they change from buttercup yellow to warm apricot and then to plum. The plants grow 3 to 4 feet tall and 4 feet wide.

Other closely related Baptisia species:

• Baptisia albescens (spiked white indigo): native to the Southeast United States, it grows 2 to 4 feet tall with white flowers and copper seed pods.
• Baptisia bracteata (false cream indigo): a compact, 24-inch plant native to the Eastern United States with long sprays of pale yellow flowers.
• Baptisia sphaerocarpa (yellow false indigo): native to the lower Midwest and Gulf states, it grows 2 to 3 feet tall and has long yellow flower spikes 12 to 15 inches long. ‘Screaming Yellow’ is a popular cultivar.
• Baptisia tinctoria (yellow false indigo): native throughout the East Coast and Midwest, it has bright yellow or creamy flowers and blooms later than other Baptisias, in later spring through early summer. Growing 2 to 3 feet tall, its flower clusters are usually only about 4 or 5 inches long.

Pruning

Because this plant takes on such a shrub-like appearance, you can also shape it by pruning, which is best done immediately after its flowering period.

In the late fall, stalks or dead stems must be trimmed off near ground level as winter sets in—or immediately in the spring before new growth begins if you prefer to leave the seed heads in place through winter. With its stately shape, false indigo makes a good architectural statement in the garden even after the flowers have faded.

Propagating False Indigo (Wild Indigo)

You can start Baptisia plants from seed, but they are slowly established. On the plus side, these are very long-lived plants that may outlive their owners. Because false indigo plants have long taproots, they are difficult to divide but grow well from stem cuttings. Here’s how to do it:

1. In April to early May, use a sharp pruner to take stem cuttings about 6 inches long, containing at least two sets of leaves and at least one set of leaf buds near the bottom of the cutting.
2. Dip the end of the cutting in rooting hormone and plant it in a small pot filled with standard potting mix. Moisten the potting mix.
3. Place the pot and cutting in a plastic bag or other plastic covering. Keep the pot in a bright, uniformly warm location, monitoring it frequently and lightly watering it if the potting mix dries out. In about eight weeks, the cutting should be rooted.
4. When the cutting has rooted, remove the plastic and continue growing the new plant until it is large enough to plant in the garden.

How to Grow False Indigo (Wild Indigo) From Seed

Growing false indigo from seed is possible, though not recommended, since it is a slow-growing plant requiring patience. False indigo seeds have a hard outer coating, and scarification will improve germination. To improve germination success, soak the seeds in hot water for at least eight hours before scarifying them. Some gardeners have luck simply planting the seeds in the fall and allowing the winter weather to soften the seed coat.

The plants take three to four years to develop the size required for meaningful blooms. They spread slowly, and a mature clump looks like a unique shrub in the landscape. Most people propagate these plants through stem cuttings for faster results.

Here’s how to sow seeds:

1. Scarify the seeds using sandpaper. Scratch the seed surface, taking care not to sand down to the inner part of the seed.
2. Ensure cold stratification by placing the scarred seed in a moist medium, like a wet paper towel, in a zip-top plastic bag in the refrigerator for at least 30 days. Check the seed regularly for sprouting while in the bag, then plant the seed. Or, plant the seed in the fall before the winter begins to naturally stratify with the cold winter season.
3. In a container or the ground, plant seeds 14 inch deep into a well-draining potting mix, like peat moss or fine vermiculite sand. Space the seeds at least two to three inches apart.
4. Keep the soil moist, watering regularly, but never soggy.
5. Place it in a sunny location.
6. Germination can occur one to four weeks after the last frost date or after stratifying, assuming stratification was successful.

Overwintering

These plants do not require a winterizing routine. Many people cut off the stems to ground level as winter approaches, but even this can be omitted if you want to leave the seed pods in place for winter interest. In borderline zones where winters are damp and above freezing, clearing the ground of plant debris is a good idea to keep the soil from being too soggy and possibly causing root rot.

Common Pests & Plant Diseases

Fungus diseases such as leaf spot, powdery mildew, and rust can occur if grown in crowded, damp conditions. Be sure to provide good air circulation around your Baptisia plants.

Weevils have been known to eat Baptisia seeds, but this is a problem only if you save the seeds to plant. Butterfly larvae may feed on the plant foliage but not enough to harm the plant. Deer, rabbits, and groundhogs rarely bother it.

How to Get False Indigo (Wild Indigo) to Bloom

Getting false indigo to bloom is a matter of patience. It can take three or four years, or even more before the clump is mature enough to make a meaningful display. Even a young nursery plant will take at least a year to establish before you start seeing it bloom.

Bloom Months

Wild indigo typically blooms from April to June.

How Long Does False Indigo Bloom?

False indigo blooms usually last three to six weeks. They bloom occasionally and will not rebloom until the next growing season. These plants are long-lived, living decades, and are reliable yearly rebloomers.

What Do False Indigo Flowers Look and Smell Like?

Flowers form on the top of plants in long panicles or sprays of pink, blue, purple, or yellow flowers. Deep blue or indigo-colored is the most common, giving its common name. Each flower is about 1 inch, shaped like sweet-pea flowers. The flowers have no discernible fragrance.

How to Encourage More Blooms

False indigo needs full sun to promote full blooms. A plant growing in shady conditions may experience reduced blooming. Remove or deeply prune nearby trees and shrubs that shade the plant to increase blooming.

Pruning too early, such as in the spring, before the flower buds have developed, can compromise flowering.

Caring for False Indigo (Wild Indigo) After It Blooms

After flowering in summer, it’s safe to prune the shrub to give it shape.

Deadheading False Indigo (Wild Indigo) Flowers

If you do not deadhead the flowers, you will get attractive seed pods similar to pea pods, which turn dark and rattle in the breeze. You can prevent this by giving your false indigo a modest shearing after flowering.

Common Problems With False Indigo (Wild Indigo)

False indigo plants are adaptable and reliably perennial in USDA hardiness zones 3 to 9. Maintenance is minimal. Here are a couple of issues you might encounter with false indigo.

Flopping Plants

When the plant grows in shady conditions, the stems may grow leggy in their effort to reach the sun, causing them to eventually flop over, usually from the center outward. Sometimes, pruning surrounding trees can increase the amount of sun and prevent this flopping. A large segmented hoop support can also help keep the stems upright. Relatively hard pruning after flowering is complete can also keep the plants shorter and bushier, eliminating the flopping problem.

Crown Rot

In soils that are too water-saturated for long periods, false indigo may develop root rot that causes the plant to turn mushy and collapse. Soil amendments around the plant can improve the soil’s drainage. Some earthmoving to redirect water can also help eliminate puddling that causes root rot. Badly affected plants are not salvageable and will need to be removed.