Sisyrinchium micranthum
blue pigroot
SunFull Sun – Part Shade
Overview
Sisyrinchium micranthum is a small tufted annual to short-lived perennial in the iris family, forming grass-like clumps 4-12 in (10-30 cm) tall. The flattened, narrow leaves are 1-4 in (2.5-10 cm) long and arranged in a fan, with winged flowering stems. Flowers are 0.3-0.5 in (8-13 mm) across, pale lilac to whitish with darker veins and a yellow center, opening singly from a pair of leaf-like bracts. Each flower lasts a single day, opening in morning sun and closing by afternoon, followed by small round capsules holding numerous black seeds. Native to South America, it has naturalized widely across warm-temperate and subtropical regions, including the southern United States, eastern Asia, and Australia, where it grows in lawns, disturbed ground, roadsides, and open grassland. It self-sows readily and can spread into a weed in moist turf and garden beds. It grows in USDA zones 8 to 10, tolerates poor soils, and is short-lived in deep shade or saturated ground.
Native Range
Sisyrinchium micranthum is native to South America, including Brazil, Argentina, Uruguay, and neighboring regions. It has naturalized across many warm-temperate and subtropical areas worldwide, such as the southern United States, eastern Asia, and Australia.Suggested Uses
Sometimes used in meadow plantings, rock gardens, and naturalistic borders for its small spring flowers. It can also colonize lawns and disturbed areas where allowed to self-seed.How to Identify
Appearance
Size & Dimensions
Height4" - 1'
Width/Spread4" - 8"
Bloom Information
Detailed Descriptions
Flower Description
pale lilac to white with a yellow centerFoliage Description
greenGrowing Conditions
Sun Requirements
Requires 6-10 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
Water & Climate
Water Needs
Drought Tolerance
Drought tolerant when established
Care & Maintenance
Care Guide
Sisyrinchium micranthum grows in full sun to light shade and adapts to a wide range of soils, including poor and sandy ones, with pH from 5.5 to 7.5. It grows as a cool-season plant in mild climates and completes its cycle quickly in a single season. Water needs are low to moderate; it tolerates seasonal dryness but declines in waterlogged soil. It self-sows readily and naturalizes in lawns and open ground. In garden settings it can become weedy where conditions suit it.Pruning
Shearing or mowing spent plants before the capsules ripen limits prolific self-seeding. No structural pruning is needed for this small herbaceous plant.Container Growing
✓ Suitable for container growing
Minimum container size: 1 gallons
⚠️ Toxicity Warning
UnknownPlanting Guide
Planting Methods & Timing
Planting Method
direct sow
Plant Spacing
6 inches