# Indigobush (Amorpha fruticosa)

> Purple flower spikes with orange stamens in June, on a nitrogen-fixing shrub for streambanks and hot dry edges.

Also called false indigo, false indigo bush, desert false indigo. Category: Native Shrubs. Grown from seed by Blue Whale Trees. Web version: https://bluewhaletrees.com/plants/indigobush/

![Indigobush (Amorpha fruticosa) purple flower spike with orange anthers above pinnate leaves](https://bluewhaletrees.com/img/plants/indigobush-h1610-800.jpg)
*Photo: Dalgial, CC BY-SA 3.0, cropped · [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Amorpha_fruticosa_05.JPG)*

## Facts

- Type: Shrub
- Mature height: 6 to 12 ft
- USDA hardiness zones: 4 to 9
- Grows wild in: Stream banks and floodplain forests
- Native range: 34 states and [the District of Columbia](https://bluewhaletrees.com/tools/native/index.html.md?state=DC), north to [North Dakota](https://bluewhaletrees.com/tools/native/index.html.md?state=ND), south to [Florida](https://bluewhaletrees.com/tools/native/index.html.md?state=FL) and west to [California](https://bluewhaletrees.com/tools/native/index.html.md?state=CA) ([Alabama](https://bluewhaletrees.com/tools/native/index.html.md?state=AL), [Arizona](https://bluewhaletrees.com/tools/native/index.html.md?state=AZ), [Arkansas](https://bluewhaletrees.com/tools/native/index.html.md?state=AR), [California](https://bluewhaletrees.com/tools/native/index.html.md?state=CA), [Colorado](https://bluewhaletrees.com/tools/native/index.html.md?state=CO), [Delaware](https://bluewhaletrees.com/tools/native/index.html.md?state=DE), [Florida](https://bluewhaletrees.com/tools/native/index.html.md?state=FL), [Georgia](https://bluewhaletrees.com/tools/native/index.html.md?state=GA), [Illinois](https://bluewhaletrees.com/tools/native/index.html.md?state=IL), [Indiana](https://bluewhaletrees.com/tools/native/index.html.md?state=IN), [Iowa](https://bluewhaletrees.com/tools/native/index.html.md?state=IA), [Kansas](https://bluewhaletrees.com/tools/native/index.html.md?state=KS), [Kentucky](https://bluewhaletrees.com/tools/native/index.html.md?state=KY), [Louisiana](https://bluewhaletrees.com/tools/native/index.html.md?state=LA), [Maryland](https://bluewhaletrees.com/tools/native/index.html.md?state=MD), [Minnesota](https://bluewhaletrees.com/tools/native/index.html.md?state=MN), [Mississippi](https://bluewhaletrees.com/tools/native/index.html.md?state=MS), [Missouri](https://bluewhaletrees.com/tools/native/index.html.md?state=MO), [Nebraska](https://bluewhaletrees.com/tools/native/index.html.md?state=NE), [New Jersey](https://bluewhaletrees.com/tools/native/index.html.md?state=NJ), [New Mexico](https://bluewhaletrees.com/tools/native/index.html.md?state=NM), [North Carolina](https://bluewhaletrees.com/tools/native/index.html.md?state=NC), [North Dakota](https://bluewhaletrees.com/tools/native/index.html.md?state=ND), [Ohio](https://bluewhaletrees.com/tools/native/index.html.md?state=OH), [Oklahoma](https://bluewhaletrees.com/tools/native/index.html.md?state=OK), [Pennsylvania](https://bluewhaletrees.com/tools/native/index.html.md?state=PA), [South Carolina](https://bluewhaletrees.com/tools/native/index.html.md?state=SC), [South Dakota](https://bluewhaletrees.com/tools/native/index.html.md?state=SD), [Tennessee](https://bluewhaletrees.com/tools/native/index.html.md?state=TN), [Texas](https://bluewhaletrees.com/tools/native/index.html.md?state=TX), [Virginia](https://bluewhaletrees.com/tools/native/index.html.md?state=VA), [West Virginia](https://bluewhaletrees.com/tools/native/index.html.md?state=WV), [Wisconsin](https://bluewhaletrees.com/tools/native/index.html.md?state=WI), [Wyoming](https://bluewhaletrees.com/tools/native/index.html.md?state=WY) and [the District of Columbia](https://bluewhaletrees.com/tools/native/index.html.md?state=DC)). Also recorded, not native, in [Connecticut](https://bluewhaletrees.com/tools/native/index.html.md?state=CT), [Idaho](https://bluewhaletrees.com/tools/native/index.html.md?state=ID), [Maine](https://bluewhaletrees.com/tools/native/index.html.md?state=ME), [Massachusetts](https://bluewhaletrees.com/tools/native/index.html.md?state=MA), [Michigan](https://bluewhaletrees.com/tools/native/index.html.md?state=MI), [New Hampshire](https://bluewhaletrees.com/tools/native/index.html.md?state=NH), [New York](https://bluewhaletrees.com/tools/native/index.html.md?state=NY), [Oregon](https://bluewhaletrees.com/tools/native/index.html.md?state=OR), [Rhode Island](https://bluewhaletrees.com/tools/native/index.html.md?state=RI), [Utah](https://bluewhaletrees.com/tools/native/index.html.md?state=UT), [Vermont](https://bluewhaletrees.com/tools/native/index.html.md?state=VT) and [Washington](https://bluewhaletrees.com/tools/native/index.html.md?state=WA)
- Sun: Full, Part
- Soil moisture: Dry, Average, Wet
- Growth rate: Fast
- Flowers: May to June
- Fruit: Pods, August
- First crop: 1 year after planting (transplants in seed production plots)
- Mature spread: 15 ft
- Traits: Showy flowers, Wildlife value, Nitrogen fixing, Drought tolerant, Tolerates wet soil, Erosion control
- Sold as: Saplings, Seed

Heights and zones are typical ranges for the species in cultivation; local conditions and seed source shift them.

## Availability

Saplings ship [bare-root](https://bluewhaletrees.com/articles/planting-bare-root-trees-on-arrival/index.html.md) or [in a pot](https://bluewhaletrees.com/articles/a-sapling-in-a-pot/index.html.md), [usually 12 to 18 inches tall](https://bluewhaletrees.com/articles/small-sapling-or-big-transplant/index.html.md), in the dormant season, and their [height and age](https://bluewhaletrees.com/articles/reading-a-nursery-listing/index.html.md) are stated with the price, once available. Live plants ship February to May and October to November. Not priced yet: leave an email on the web page for one email when it is priced, with a code for 10% off the plants in that order, not shipping or tax, or write to captain@bluewhaletrees.com.

## Notes

Indigobush is a legume shrub of riverbanks and prairies that handles both flooding and drought. Its bloom draws a crowd of native bees and it hosts several butterflies. Fast and loose in habit; cut it back hard in spring to keep it dense. Excellent for stabilizing banks and for pollinator hedges. Belongs in a rain garden or a ditch that floods in spring and bakes by August.

## Size, growth and what to expect

Indigobush flowers young. In seed production plots at the Tallgrass Prairie Center, transplants flowered and set seed the year after planting. Growth is fast, and our growth estimator models it at nearly three feet a year on an average site. It makes a loose, airy shrub of 6 to 12 feet that spreads into a thicket of cane-like stems, branching only above 3 or 4 feet.

The purple spikes run 3 to 6 inches long and open in June, and the small warty pods that follow are under half an inch long, each holding a single seed. Bees and butterflies take the nectar, and it is a larval host for the silver-spotted skipper and the gray hairstreak. Nodules on its roots fix nitrogen that neighboring plants can share. The name false indigo comes from early settlers who used it as a substitute for true indigo dye.

It grows wild from New Jersey west to Minnesota and Wyoming, south to Florida and Texas, and from southern California to New Mexico. It grows on wet ground along rivers, streams, ponds and ditches, and on gravel bars.

## How to grow Indigobush

Indigobush grows anywhere in full sun or part shade, on a dry bank, ordinary garden soil, or ground that floods in spring. Full sun gives the heaviest bloom and the sturdiest stems. Plants lean outward, so allow 6 feet between them and keep them off a walk.

Plant dormant stock from leaf fall to bud break. Saplings come bare-root or potted. Dig twice the width of the roots, keep the crown at ground level, backfill with native soil, and mulch short of the stems. No stake is wanted. Seed is a hard-coated legume, so nick the coat, soak it overnight, and sow in fall under hardware cloth, or mice will clean out the bed.

Water the first summer and it takes over from there. Rabbits clip young stems in winter, so cage new plants a season or two. Cutting it hard in late winter costs no bloom, since flowers come on the current year's shoots.

Each flower carries both male and female parts and bees pollinate it, so there are no male and female plants to pair. The warning with false indigo is seed. It fruits freely, birds and water carry it, and it has made a nuisance of itself along rivers outside its home range. Maine, Connecticut, Oregon and Washington ban its sale or its entry, so we do not send it to those four states. On a small lot, cut the spikes before the pods ripen.

## Sources

- [USDA NRCS Plant Guide, Desert False Indigo](https://plants.sc.egov.usda.gov/DocumentLibrary/plantguide/pdf/pg_amfr.pdf)
- [NC State Extension Gardener Plant Toolbox, Amorpha fruticosa](https://plants.ces.ncsu.edu/plants/amorpha-fruticosa/)
- [Lady Bird Johnson Wildflower Center, Amorpha fruticosa](https://www.wildflower.org/plants/result.php?id_plant=amfr)
- [Tallgrass Prairie Center, University of Northern Iowa, false indigo bush production guide](https://tallgrassprairiecenter.org/native-seed-production-manual/species-production-guides/woody-species/false-indigo-bush)
- [USDA NRCS PLANTS Database: Amorpha fruticosa](https://plants.usda.gov/plant-profile/AMFR)
- [USDA Forest Service, Woody Plant Seed Manual (2008), Amorpha chapter, Zasada and Martineau](https://www.fs.usda.gov/nsl/Wpsm/Amorpha.pdf)
- [Grabić, Ljevnaić-Mašić, Zhan, Benka and Heilmeier 2022, A review on invasive false indigo bush (Amorpha fruticosa L.): Nuisance plant with multiple benefits, Ecology and Evolution 12: e9290](https://pmc.ncbi.nlm.nih.gov/articles/PMC9475134/)
- [The Morton Arboretum: indigo bush](https://mortonarb.org/plant-and-protect/trees-and-plants/indigo-bush/)
- [Minnesota Wildflowers: Amorpha fruticosa, false indigo](https://www.minnesotawildflowers.info/shrub/false-indigo)
- [Virginia Tech Dendrology: desert false indigo, Amorpha fruticosa](https://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=772)
- [Go Botany, Native Plant Trust: Amorpha fruticosa](https://gobotany.nativeplanttrust.org/species/amorpha/fruticosa/)
- [Missouri Botanical Garden Plant Finder: Amorpha fruticosa](https://plantfinder.mobot.org/PlantFinderDetails.aspx?taxonid=280343)

## Read before planting

- [Ten planting mistakes that quietly kill trees](https://bluewhaletrees.com/articles/ten-planting-mistakes/index.html.md)
- [Transplanting young trees: timing, water and protection](https://bluewhaletrees.com/articles/transplanting-young-trees/index.html.md)
- [Protecting young trees from voles, rabbits, deer and squirrels](https://bluewhaletrees.com/articles/protecting-trees-from-animals/index.html.md)
- [Native trees and shrubs that fix nitrogen, and the legumes that do not](https://bluewhaletrees.com/articles/native-trees-and-shrubs-that-fix-nitrogen/index.html.md)
- [Pruning and renewing native shrubs: when each kind is cut, and which never need it](https://bluewhaletrees.com/articles/pruning-and-renewing-native-shrubs/index.html.md)
- [The habitat around a tree is part of the tree](https://bluewhaletrees.com/articles/habitat-around-a-tree/index.html.md)

## Related

- We grow 7 other indigobushes (Amorpha): [all of them](https://bluewhaletrees.com/shop/index.html.md?q=amorpha)
- Plants that share its sun and soil: [Trumpet Creeper](https://bluewhaletrees.com/plants/trumpet-creeper/index.html.md), [Riverbank Grape](https://bluewhaletrees.com/plants/riverbank-grape/index.html.md), [Possumhaw](https://bluewhaletrees.com/plants/possumhaw/index.html.md) and [Roughleaf Dogwood](https://bluewhaletrees.com/plants/roughleaf-dogwood/index.html.md)
- Trees to plant it under: [American Elm](https://bluewhaletrees.com/plants/american-elm/index.html.md), [Slippery Elm](https://bluewhaletrees.com/plants/slippery-elm/index.html.md) and [Sugarberry](https://bluewhaletrees.com/plants/sugarberry/index.html.md)
- Same size, similar character: [Leadplant](https://bluewhaletrees.com/plants/leadplant/index.html.md), [Ouachita Indigobush](https://bluewhaletrees.com/plants/ouachita-indigobush/index.html.md), [Schwerin's Indigobush](https://bluewhaletrees.com/plants/schwerin-indigobush/index.html.md) and [Clusterspike Indigobush](https://bluewhaletrees.com/plants/clusterspike-indigobush/index.html.md)
- [Planting-site check](https://bluewhaletrees.com/tools/site-check/index.html.md): for a thrive, struggle or fail verdict on Indigobush (False Indigo), add ?species=indigobush with zone (2 to 10), sun (full, part, shade) and moisture (dry, average, wet) to that address; for example, the verdict for zone 4, part sun and average soil as Markdown is at https://bluewhaletrees.com/tools/site-check/index.html.md?species=indigobush&zone=4&sun=part&moisture=average
- [Companion species for Indigobush (False Indigo)](https://bluewhaletrees.com/tools/companions/index.html.md?species=indigobush): the natives that share its ground and the plants that pair with it in a yard.
- [Tree growth estimator](https://bluewhaletrees.com/tools/growth/index.html.md): how the height and trunk projections are made; the estimate for Indigobush (False Indigo) as Markdown is at https://bluewhaletrees.com/tools/growth/index.html.md?species=indigobush (add height=, years= and site= poor, average or good)
- [Seed sowing planner](https://bluewhaletrees.com/tools/sowing/index.html.md): how Indigobush (False Indigo) is sown, in the chart for every species (treatment, cold days, depth, timing); the dated plan for it as Markdown is at https://bluewhaletrees.com/tools/sowing/index.html.md?species=indigobush (add state= and zone= for your own frost dates, method=fridge for the refrigerator route)
- [Pollination planner](https://bluewhaletrees.com/tools/pollination/index.html.md): what Indigobush (False Indigo) needs for a crop and how many to plant, in the table for every species; the verdict for 1 of them as Markdown is at https://bluewhaletrees.com/tools/pollination/index.html.md?plants=indigobush:1
- [Planting-window tool](https://bluewhaletrees.com/tools/planting-window/index.html.md): when to plant Indigobush (False Indigo) where you live, as a fall and a spring window from the local frost dates; the windows as Markdown are at https://bluewhaletrees.com/tools/planting-window/index.html.md?species=indigobush&state=MO&zone=6 with your own state and zone in place of those
- [Planting-distance tool](https://bluewhaletrees.com/tools/distance/index.html.md): how far Indigobush (False Indigo) goes from a house, a septic field, a walk, wires, a property line and the next tree; the distances as Markdown are at https://bluewhaletrees.com/tools/distance/index.html.md?species=indigobush&near=house,septic,pavement,wires,boundary,tree
- [Bloom and fruit calendar](https://bluewhaletrees.com/tools/calendar/index.html.md): the months Indigobush (False Indigo) flowers and fruits, in the grid for every species; its own row and the gaps of a planting with it as Markdown at https://bluewhaletrees.com/tools/calendar/index.html.md?plants=indigobush