Quackgrass (Elymus repens) (L.) Gould Origin Native to Europe. Appearance E. repens is a perennial, cool-season, rhizomatous grass that can grow up to 3′ (0.9 m) tall. Foliage The stems are green to whitish, erect to decumbent and can grow to 3′ (0.9 m) tall. The leaves are 6-15.7″ (15.2–40 cm) long and usually have a pair of prominent auricles at the base. Flowers Flowering occurs from May to September. The flower spikes are 3.9–11.8″ (10–30 cm) long and have 3-8 yellow florets per spikelet. Fruit Seeds form a spool-shaped unit, broadest below the middle and are usually brown, 0.16–0.20″ (4–5 mm) long. Seeding occurs from spring to summer. Ecological Threat E. repens is intolerant to shade and occurs in pastures, gardens, roadsides, and other disturbed open areas.