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CROTALARIA juncea

Image of Crotalaria juncea

Family

Fabaceae

Botanical Name

CROTALARIA juncea

Plant Common Name

Brown Hemp, Indian Hemp, Madras Hemp, Sunn hemp

General Description

Prized as an agricultural forage plant for livestock and a source of fiber stronger than jute, sunn hemp is also an attractive plant producing deep yellow flowers. This upright annual, most likely native to India and Pakistan, is widely cultivated across the tropics in both the wet and dry seasons. In temperate regions, it's sometimes planted as a bedding annual.

The fast-growing sunn hemp is large, shrubby and has elongated light green to gray-green leaves. Flowering is most prolific in the fall and winter when days are shorter, which is why it's most commonly grown in tropical and subtropical locations. Its stem tips produce upright clusters of deep yellow, pea-like flowers that attract bees. The fruits are inflated tan pods that split open to reveal dark gray to black seeds.

Grow sunn hemp in any sunny location. It is tolerant of a wide range of soil types but grows best in well-drained, light soils with average moisture and fertility. Long days and abundant rain promotes foliar growth, which is ideal for fiber production. Those more interested in flowers should consider planting sunn hemp in mid to late summer for fall flowering.

The fiber extracted from semi-woody stems is used to make twine, yarn, paper, sacks and canvas. Sunn fiber is stronger when wet and resists rot and deterioration when wet, even if exposed to salt water.

This species is known to become weedy and invasive in frost-free locations worldwide.

Characteristics

  • AHS Heat Zone

    12 - 4

  • Sunset Zone

    H1, H2, 3a, 3b, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 24

  • Plant Type

    Annual

  • Sun Exposure

    Full Sun, Partial Sun

  • Height

    3'-10' / 0.9m - 3.0m

  • Width

    3'-8' / 0.9m - 2.4m

  • Bloom Time

    Indeterminate

  • Native To

    Southern Asia, India

Growing Conditions

  • Soil pH

    Neutral

  • Soil Drainage

    Well Drained

  • Soil type

    Clay, Loam, Sand

  • Growth Rate

    Very Fast

  • Water Requirements

    Drought Tolerant, Average Water

  • Habit

    Oval/Rounded

  • Seasonal Interest

    Spring, Summer, Fall, Winter

Ornamental Features

  • Flower Interest

    Showy

  • Flower Color

    Yellow, Gold

  • Fruit Color

    Black

  • Foliage Color (Spring)

    Light Green, Gray Green

  • Foliage Color (Summer)

    Light Green, Gray Green

  • Foliage Color (Fall)

    Light Green, Gray Green

  • Foliage Color (Winter)

    Light Green, Gray Green

  • Fragrant Flowers

    Yes

  • Fragrant Fruit

    No

  • Fragrant Foliage

    No

  • Bark or Stem Fragrant

    No

  • Flower Petal Number

    Single

  • Repeat Bloomer

    Yes

  • Showy Fruit

    No

  • Edible Fruit

    No

  • Showy Foliage

    No

  • Foliage Texture

    Fine

  • Foliage Sheen

    Matte

  • Evergreen

    No

  • Showy Bark

    No

Special Characteristics

  • Usage

    Bedding Plant, Mixed Border, Tropical

  • Sharp or Has Thorns

    No

  • Invasive

    Sometimes

  • Self-Sowing

    Yes