Practical
Plants

Amorpha fruticosa

False Indigo

a perennial woody deciduous member of the Amorpha genus in the family Leguminosae.

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Taxonomy and growth

Genus
Amorpha
Life cycle
perennial
Foliage
deciduous
Woodiness
woody
Growth rate
moderate
Height
4.5 m
Flower type
hermaphrodite

Uses

Toxicity

Toxicity warning. The historical record reports a hazard for this plant. Do not use it to decide which parts are safe to eat or use medicinally.

The plant is said to contain alkaloids and be poisonous to livestock[9].

Edible uses

The crushed fruit is used as a condiment[1][4][5].

Product or use
Condiment

Material uses

Plants have an extensive root system and are also fairly wind tolerant, they can be planted as a windbreak and also to prevent soil erosion[7]. Resinous pustules on the plant contain 'amorpha', a contact and stomachic insecticide that also acts as an insect repellent[12][7]. The stems are used as bedding[13]. The plant contains some indigo pigment and can be used to make a blue dye[3]. Unfortunately, the pigment is only present in very small quantities, there is not enough to harvest commercially[3].

Product or use
Bedding
Product or use
Dye
Product or use
Insecticide
Product or use
Oil
Product or use
Repellent

Environment

Range
Southern N. America. Locally naturalized in S. and C. Europe[11].
Habitat
River banks, rich moist thickets etc[10][6]. Grows chiefly in limestone soils[9].
Light
full sun
Shade tolerance
light shade
Water
moderate
Hardiness
Zone 4+
Soil textures
sandy, loamy
Soil pH
acid, neutral, alkaline
Drainage
well drained
Tolerances
high wind, drought
Wind
Yes
Tolerates Nutritionally Poor Soil
No
Drought
tolerant

Propagation

Seed - pre-soak for 12 hours in warm water and then sow early spring in a greenhouse[14][2]. The seed usually germinates in 1 - 2 months at 20°c[2]. When large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter. Plant them out in late spring or early summer, after the last expected frosts. Cuttings of half-ripe wood, June/July in a frame. High percentage[14]. Cuttings of mature wood of the current seasons growth, autumn, in a sheltered position outdoors. Takes 12 months[14]. Suckers in spring just before new growth begins[7]. Layering in spring .

Cultivation

Prefers a light well-drained sandy soil in sun or light shade[6][7]. Plants are fairly wind-resistant[7]. A very hardy plant, tolerating temperatures down to about -25c[6][7]. A polymorphic species, there are many named forms[10]. The flowers have a vanilla perfume[8]. Plants resent root disturbance, they should be planted out into their final positions whilst small[2]. Trees only ripen their seed in fine autumns[15]. Plants are said to be immune to insect pests[7]. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[7].

References

  1. Tanaka. T. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing 1976-00-00

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  2. Rice. G. (Editor) Growing from Seed. Volume 1. Thompson and Morgan. 1987-00-00

    ↩1↩2↩3

  3. Buchanan. R. A Weavers Garden.

    ↩1↩2

  4. Kunkel. G. Plants for Human Consumption. Koeltz Scientific Books 1984-00-00 ISBN 3874292169

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  5. Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990-00-00 ISBN 0-9628087-0-9

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  6. Phillips. R. & Rix. M. Shrubs. Pan Books 1989-00-00 ISBN 0-330-30258-2

    ↩1↩2↩3

  7. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3↩4↩5↩6↩7↩8

  8. Genders. R. Scented Flora of the World. Robert Hale. London. 1994-00-00 ISBN 0-7090-5440-8

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  9. Diggs, Jnr. G.M.; Lipscomb. B. L. & O'Kennon. R. J Illustrated Flora of North Central Texas Botanical Research Institute, Texas. 1999-00-00 http://artemis.austincollege.edu/acad/bio/gdiggs/NCTXpdf.htm

    ↩1↩2

  10. Fernald. M. L. Gray's Manual of Botany. American Book Co. 1950-00-00

    ↩1↩2

  11. ? Flora Europaea Cambridge University Press 1964-00-00

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  12. Schery. R. W. Plants for Man.

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  13. Usher. G. A Dictionary of Plants Used by Man. Constable 1974-00-00 ISBN 0094579202

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  14. Sheat. W. G. Propagation of Trees, Shrubs and Conifers. MacMillan and Co 1948-00-00

    ↩1↩2↩3

  15. McMillan-Browse. P. Hardy Woody Plants from Seed. Grower Books 1985-00-00 ISBN 0-901361-21-6

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