Butomus umbellatus – Flowering Rush – Butomaceae (Eurasia)
Habit: Thicket-like rush, stiffly upright, forming large crops with runners.
Average size: 50-150 cm tall; number/m²: 5-7.
Flowers: Small bowls, pink-white with pink veins, long peduncles in 20 cm wide, domed umbels; July to September; not flowering at water depths below 50 cm.
Leaves: Like grass, slenderly linear, three-edged, dark green.
Demands: Sun, does not tolerate shade heat, likes warmth, frost hardy.
Soil: Swamps to flooded areas, stagnant or slowly flowing water, water depths 20-50 (150) cm.