Indigofera

( in - dig - GOFF - er -uh )

At-A-Glance Information

Indigofera, commonly called Indigo Bush, is a genus of flowering deciduous shrubs and small trees that require regular water. They have woody growth and ferny foliage, and are beautiful, versatile additions to gardens. Flowers are small and clustered, appearing in spring, summertime and fall. These plants are sensitive to frost conditions, and are native to tropical areas throughout the globe. Indigo Bush has been used historically for thousands of years to produce blue dye used for coloring clothing and other textiles. Take care when planting these trees and shrubs in the landscape, as some species contain toxic compounds, and should not be consumed by humans or pets.

Indigofera Species and Varietals

This genus Indigofera includes 750 species and is a member of the Legume plant family Fabaceae. The genus name is derived from the Latin words for 'blue dye' (indigo) and 'to bear' (fera). Indigo Bush grows best in zones 2b-9 and 14-21. For more growing information, see the descriptions below. To find your zone, click here: Zone Map.

Indigofera amblyantha (Chinese Indigo, Pink-Flowered Indigo)
This species is native to central and southern China, and is a shrub that forms upright stems covered with green leaves and topped with pink flowers. Individual shrubs reach up to 6 feet tall and bloom from May through September. A popular choice for mixed beds, hedges, borders, massing, and containers.

Indigofera australis (Austral Indigo, Australian Indigo)
This shrub native to Australia grows best in zones 14-24, and gets 5 feet tall and wide. Magenta flowers bloom in clusters from July through November. This species needs partial shade and can tolerate salty soils.

Indigofera decora (Indigofera incarnata) (Summer Wisteria)
This species is native to China and Japan, and gets 1 to 2.5 feet tall and 3 feet wide. Has arching branches and narrow, drooping flower clusters of white and pink. Needs full sun. These wide, spreading shrubs are somewhat drought and heat tolerant, but do prefer late afternoon shade.

Indigofera hilaris (Red Bush Indigo, Gay Indigofera)
These plants are perennial shrublets that form erect stems and green foliage. Flowers are reddish-pink to carmine-colored, and bloom from July to December in the plant's native range (Africa).

​Indigofera kirilowii (Kirilow's Indigo)
This species is native to northern China, Korea and Japan, and can reach 2.5-3 feet tall and 3 feet wide. Shoots of flowers are erect and rose-pink. Requires full sun.

Indigofera pendula (Weeping Indigo)
This species is native to south-central China. They reach up to 10 feet tall and 3 feet wide. Flowers are pink and hang from branches in loose panicles. Cultivar 'Shangri-la' is a choice ornamental for landscapes.

Indigofera suffruticosa (Guatemalan Indigo, Small-Leaved Indigo, West Indian Indigo, Wild Indigo, Anil)
These plants are native to subtropical and tropical areas in the Americas, and has been introduced to many other areas around the globe. It forms an erect, branching shrub to 3.3 feet tall and is typically found in disturbed soils.

Caring for and pruning Indigofera shrubs

Indigofera shrubs thrive in moist, well-draining soil with a neutral pH. Frost can kill these shrubs to the ground, but they will regrow and bloom on new wood the following season. These shrubs need hard pruning during their dormant season (usually best done in early springtime) to keep a compact, attractive shape. Fertilize once a year with a slow-release, balanced fertilizer in early springtime, and mulch around the base of the plant to increase soil moisture retention and protect roots from cooler temperatures.

Propagation

Indigofera can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your shrub, follow the instructions below:

Propagating Indigofera by Cutting
  1. Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
  2. In summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 3-6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
  3. Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
  4. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Propagating Indigofera by Seed
  1. Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
  2. Harvest your seeds. The seed pods on these plants are pretty easy to spot, they're large and dangle from the branches, left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
  3. Indigofera seeds have a hard coating that protects them, but this coating also makes it a little difficult to get them to germinate. We can help the process along by scarifying them with sandpaper (or simply rubbing them against an abrasive surface). Do this with as many seeds as you can; they will probably not all sow, and the ones that do will be of varying characteristics. The more seeds you plant, the more chances you will have to get the resulting shrub you want. Place your seeds in lukewarm water for six hours. Viable seeds will sink to the bottom, and non-viable seeds will float to the top. You can discard any seeds that float.
  4. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 15-30 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
  5. Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 70 and 80 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Seeds are contained inside pods; they will turn brown and get dry when they are ready to be harvested from the shrub.
Indigofera seeds.

Problems and Pests

Indigofera doesn't commonly suffer from any serious pest or diseases, but it can be susceptible to the following if the right growing conditions aren't met:
  • ​Rust
  • Root Rot
  • Crown Rot
For information on these issues, including how to treat and prevent them, see the following links:
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Gallery

Camellias are great candidates to be grown as container plants on your patio.
A field of thea sinensis
Camellia hiemalis 'Shishi Gashira'

Videos

How Indigo Bush is used to make natural dyes.
Propagating camellias

Resources

How to Propagate Indigo Plants from Seed
How to Grow and Care for Indigo Plants
Indigofera
Wikipedia: Indigofera
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 374 - 375, Indigofera
If you have any questions, comments, concerns, or photos you’d like to add to the gallery, please let me know by sending me a message using the button below!
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