Roundfruit rush (Juncus compressus)
Common Names: Flattened rush, compressed rushDescription: Introduced to North America by the American military as feed for horses.
Habit: Perennial, grass-like herb that can grow to 80 cm tall.
Leaves: 2-14 in. long, up to 2 mm. wide, flattened, often channeled, lacking septa. Sheath is open at front, 2 lobes at the tip that are 0.3-0.5 mm. long, rounded, with a membranous band around edge. Flowering stems have 1-2 alternate leaves and 0-2 basal leaves.
Stems: Smooth, erect, unbranched except in flower cluster. Forms dense clumps and colonies from creeping rhizomes.
Flowers: 5-60 flowers in a loose to congested branching cluster at the top of stem, longer than wide, branches erect to ascending, singular, 6 tepals in 2 layers, 1.7-2.7 mm. long, rounded at the tip, brown to dark brown in color with green midrib and white, papery edges.
Fruit and seeds: Capsule, 3 sections, 2.5-3.5 mm. long, oval to nearly round, rounded at the tip, dark chestnut brown when mature. Contains numerous seeds that are elliptic to crescent-shaped, narrow at the tip, 0.3-0.5 mm. long dark golden brown when mature with vertical ridges and cross-bars.
Habitat: Native to Eurasia. Can be found growing in roadsides, ditches, farm fields, fence rows, and disturbed areas.
Reproduction: By seed or vegetatively by short, creeping rhizomes.
Similar species: Saltmeadow rush (Juncus gerardii)
Monitoring and rapid response: Can be controlled by using glyphosate or ammonium salt of imazapyr but these herbicides are non-selective and should be applied carefully. Glyphosate should by applied directly onto foliage in mid-late summer. There are no know physcial control methods and aphids may occasionally feed on Juncus spp. Credits: The information provided in this factsheet was gathered from Minnesota Wildflowers and the U.S. Geological Survey, Nonindigenous Aquatic Species Database.
Individual species images that appear with a number in a black box are courtesy of the Bugwood.org network (http://www.invasive.org).Individual photo author credits may not be included due to the small display size of the images and subsequent difficulty of reading the provided text. All other images appear courtesy of Google (http://images.google.com).