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
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AHS Heat Zone
12 - 4
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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
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Plant Type
Annual
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Sun Exposure
Full Sun, Partial Sun
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Height
3'-10' / 0.9m - 3.0m
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Width
3'-8' / 0.9m - 2.4m
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Bloom Time
Indeterminate
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Native To
Southern Asia, India
Growing Conditions
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Soil pH
Neutral
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Soil Drainage
Well Drained
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Soil type
Clay, Loam, Sand
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Growth Rate
Very Fast
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Water Requirements
Drought Tolerant, Average Water
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Habit
Oval/Rounded
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Seasonal Interest
Spring, Summer, Fall, Winter
Ornamental Features
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Flower Interest
Showy
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Flower Color
Yellow, Gold
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Fruit Color
Black
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Foliage Color (Spring)
Light Green, Gray Green
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Foliage Color (Summer)
Light Green, Gray Green
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Foliage Color (Fall)
Light Green, Gray Green
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Foliage Color (Winter)
Light Green, Gray Green
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Fragrant Flowers
Yes
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Fragrant Fruit
No
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Fragrant Foliage
No
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Bark or Stem Fragrant
No
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Flower Petal Number
Single
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Repeat Bloomer
Yes
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Showy Fruit
No
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Edible Fruit
No
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Showy Foliage
No
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Foliage Texture
Fine
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Foliage Sheen
Matte
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Evergreen
No
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Showy Bark
No
