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Triglochin spp.
arrowgrass
Overview
Triglochin is a genus of about 25 species of grass-like marsh herbs in the family Juncaginaceae, distributed across wetlands on every continent except Antarctica. Plants grow from short rhizomes or fibrous roots and form tufts of slender, basal leaves that are semi-cylindrical to flattened and 6-39 inches (15-100 cm) tall. The leaves sheathe the stem base and taper to a blunt or pointed tip, resembling those of rushes more than true grasses. Tiny three-parted flowers are borne in narrow, spike-like racemes held on leafless stalks above the foliage; they are green to purplish and wind-pollinated, lacking petals adapted to insects. Fruits are small, ribbed capsules that split into segments at maturity. Species occupy freshwater and brackish marshes, lake margins, and coastal saltflats, and several tolerate saline or alkaline soils. The foliage of many species contains cyanogenic compounds that can poison grazing livestock. Across the genus, habit ranges from compact annuals to spreading perennials, so growth form varies with species and site moisture.
Native Range
Species occur worldwide in wetland habitats, with native ranges spanning North and South America, Europe, Asia, Africa, and Australia. Triglochin maritima and T. palustris extend across northern temperate regions, while other species are restricted to the Southern Hemisphere.Suggested Uses
Grown in bog gardens, pond and stream margins, and rain gardens where soils stay wet. Saline-tolerant species are used in restoration of coastal salt marshes and brackish wetlands.How to Identify
Appearance
Size & Dimensions
Height6" - 3'3"
Width/Spread6" - 1'6"
Colors
Bloom Information
Flowering occurs mainly from late spring through summer, roughly May to August in temperate zones. The wind-pollinated flowers are small and green, opening progressively up the spike. Seed set follows within several weeks, with fruits ripening through late summer.
Detailed Descriptions
Flower Description
green to purplishFoliage Description
green to grey-greenGrowing Conditions
Sun Requirements
Requires 6-12 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