Overview
Setaria parviflora is a clump-forming perennial grass 1-3 feet (30-90 cm) tall, spreading from short, knotty rhizomes that give it the name knotroot. The narrow, flat leaf blades are 4-12 inches (10-30 cm) long and 0.1-0.3 inch (3-8 mm) wide, green and somewhat rough to the touch, rising from tufted bases. From summer into autumn each stem ends in a dense, cylindrical, spike-like flower head 1-4 inches (2.5-10 cm) long, the tiny flowers hidden among numerous slender bristles that give the foxtail its bristly outline. The bristles are tawny to purplish and stand erect, ageing to straw color as the seed ripens. The plant grows in moist meadows, ditches, lawns, and disturbed open ground across warm-temperate and tropical America. It spreads by both seed and creeping rhizomes and can form persistent patches that behave as a weed in turf and cultivated ground. Foliage is grazed by livestock but has limited forage value. It dies back to the rhizome in cold winters and regrows in spring.
Native Range
Native to the warmer parts of the Americas, from the southern and eastern United States south through Mexico, Central America, and South America, in moist meadows, ditches, pond edges, lawns, and disturbed ground.Suggested Uses
Used in wetland edges, rain gardens, and restoration plantings where a tough native grass is wanted on moist ground. Grown for erosion control on ditch banks and damp slopes. Its spreading rhizomes and weedy tendency restrict its use in lawns and tidy borders.How to Identify
Appearance
Size & Dimensions
Height1' - 3'
Width/Spread1' - 2'
Reaches mature size in approximately 1 years
Bloom Information
The bristly flower spikes form from summer into autumn, roughly June through October. Tiny wind-pollinated flowers are hidden among the bristles, which age from tawny or purplish to straw color as seed ripens. Wind carries the pollen, and birds and small mammals take the ripe seed.
Detailed Descriptions
Flower Description
Tawny to purplish bristlesFoliage Description
GreenGrowing Conditions
Sun Requirements
Requires 5-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight