# Ouachita Indigobush (Amorpha ouachitensis) > A rare indigobush of the Ouachita Mountains, 3 to 6 feet tall, with slender purple flower spikes up to 8 inches long in late spring. Also called Ouachita leadplant, Ouachita false indigo, Ouachita Mountain leadplant. Category: Native Shrubs. Grown from seed by Blue Whale Trees. Web version: https://bluewhaletrees.com/plants/ouachita-indigobush/ ![Ouachita indigobush (Amorpha ouachitensis) purple flower spikes among compound leaves on a wild shrub](https://bluewhaletrees.com/img/plants/ouachita-indigobush-h1610-800.jpg) *Photo: Eric Hunt, CC BY-SA 4.0 ยท [Wikimedia Commons](https://commons.wikimedia.org/wiki/File%3AAmorpha_ouachitensis_%282%29.jpg)* ## Facts - Type: Shrub - Mature height: 3 to 6 ft - USDA hardiness zones: 5 to 8 - Grows wild in: Rocky ground, dry uplands and stream banks - Native range: Arkansas and Oklahoma - Sun: Full, Part - Soil moisture: Dry, Average - Growth rate: Fast - Traits: Rare, Showy flowers, Drought tolerant, Nitrogen fixing, Wildlife value - Sold as: Saplings, Seed Heights and zones are typical ranges for the species in cultivation; local conditions and seed source shift them. ## Availability Not yet priced online. Ask at captain@bluewhaletrees.com or leave an email on the web page to be told when it is listed. ## Notes Ouachita indigobush grows wild only in the Ouachita Mountains of west-central Arkansas and southeastern Oklahoma, on rocky slopes, glades and the banks of mountain streams. Botanists long filed its plants under other indigobushes, and it was named as a species of its own only in 1975. Its leaflets are broad, with a rounded or notched tip. NatureServe ranks it vulnerable. Grow it on a dry, rocky bank or at the sunny edge of a rock garden, where its purple spikes show in late spring. ## Size, growth and what to expect No source rates its growth, so our growth estimator uses the fast rate of our indigobush, about 2.75 feet a year while young. It makes an upright shrub 3 to 6 feet tall and as wide, and a few reach about 9 feet. Each leaf runs 3 to 9 inches long, with 9 to 13 grayish green leaflets. Slender spikes 4 to 8 inches long, alone or in clusters of two to four, open from April into June. The tiny flowers are purple with yellow anthers, and butterflies visit them. Like other amorphas, it bears small pods that ripen light brown in mid to late summer. Each is about a third of an inch long and holds a single seed. It grows wild only in the Ouachita Mountains of west-central Arkansas and southeastern Oklahoma. Its home is rocky clearings along creeks, stream banks, rocky ridges and glades, and dry sandstone slopes. NatureServe counts about 56 populations, most of them small, and logging, grazing and road building threaten them. ## How to grow Ouachita Indigobush Ouachita indigobush takes full sun or part shade, in a well-drained soil that is average to dry. It does well in poor, sandy ground, and it takes drought and holds a bank against erosion. Set plants 3 feet apart and 3 feet from a wall. At its size it can go within 15 feet of overhead wires. Saplings ship bare-root or potted. Plant them dormant, in a hole wider than the roots and no deeper. Set the crown at the soil line, put the native soil back in, and keep the mulch clear of the stems. Other amorphas have a hard seed coat that a winter outdoors helps to soften. Sow the seed outdoors in fall, about a quarter inch deep. Water weekly through the first summer, then only in long droughts. It needs little care once rooted, and it can seed itself around the garden. Each flower carries both male and female parts, so there are no male and female plants to pair. Leaf spots, rust, powdery mildew and canker can turn up, though none is serious. ## Sources - [Missouri Botanical Garden Plant Finder: Amorpha ouachitensis](https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=280284&isprofile=0) - [Lady Bird Johnson Wildflower Center: Amorpha ouachitensis, Ouachita False Indigo](https://www.wildflower.org/plants/result.php?id_plant=AMOU) - [Wilbur 1975, A revision of the North American genus Amorpha (Leguminosae-Psoraleae), Rhodora 77(811): 337-409, species 14 on pages 394-397](https://archive.org/details/biostor-138235) - [NatureServe Explorer: Amorpha ouachitensis, Ouachita Leadplant](https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.159298/Amorpha_ouachitensis) - [Oklahoma Natural Heritage Inventory: tracking list](https://obis.ou.edu/tracking-list) - [U.S. Fish and Wildlife Service, ECOS: Unnamed false indigo, Amorpha ouachitensis](https://ecos.fws.gov/ecp/species/5460) - [USDA NRCS PLANTS Database: Amorpha ouachitensis, AMOU](https://plants.usda.gov/plant-profile/AMOU) - [USDA Forest Service, Woody Plant Seed Manual (2008), Amorpha chapter](https://www.fs.usda.gov/nsl/Wpsm/Amorpha.pdf) ## 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) - [The habitat around a tree is part of the tree](https://bluewhaletrees.com/articles/habitat-around-a-tree/index.html.md) - [Invasive vines and shrubs are what is killing your woods](https://bluewhaletrees.com/articles/invasive-vines-and-shrubs/index.html.md) - [Native trees and shrubs for butterflies and moths: host plants first, nectar second](https://bluewhaletrees.com/articles/native-trees-for-butterflies-and-moths/index.html.md) ## Related - [Planting-site check](https://bluewhaletrees.com/tools/site-check/index.html.md): for a thrive, struggle or fail verdict on Ouachita Indigobush, add ?species=ouachita-indigobush with zone (2 to 10), sun (full, part, shade) and moisture (dry, average, wet) to that address, for example ?species=ouachita-indigobush&zone=5&sun=part&moisture=average. - [Companion species for Ouachita Indigobush](https://bluewhaletrees.com/tools/companions/index.html.md?species=ouachita-indigobush): the natives that share its ground and the plants that pair with it in a yard. - [Growth estimator](https://bluewhaletrees.com/tools/growth/index.html.md): how the height and trunk projections are made; the estimate itself runs in the browser at https://bluewhaletrees.com/tools/growth/#species=ouachita-indigobush - [Seed sowing planner](https://bluewhaletrees.com/tools/sowing/index.html.md): how Ouachita Indigobush is sown, in the chart for every species (treatment, cold days, depth, timing); the dated plan runs in the browser at https://bluewhaletrees.com/tools/sowing/#species=ouachita-indigobush - [Pollination planner](https://bluewhaletrees.com/tools/pollination/index.html.md): what Ouachita Indigobush needs for a crop and how many to plant, in the table for every species; the planner runs in the browser at https://bluewhaletrees.com/tools/pollination/#plants=ouachita-indigobush:1 - [Bloom and fruit calendar](https://bluewhaletrees.com/tools/calendar/index.html.md): the months Ouachita Indigobush flowers and fruits, in the grid for every species.