Zoysia japonica Steud.
Family: Poaceae
Zoysia japonica image

Plants rhizomatous. Culm internodes 2-10 mm. Sheaths glabrous; ligules 0.05-0.25 mm; blades to 6.5 cm long, 0.5-5 mm wide, ascending, flat to loosely involute when fully hydrated, involute when stressed, surfaces glabrous or pilose. Peduncles exserted, extending 0.8-6.5 cm beyond the sheaths of the flag leaves. Racemes 2.5-4.5 cm, with 25-50 spikelets; pedicels 1.6-3.5 mm. Spikelets 2.5-3.4 mm long, 1-1.4 mm wide, ovate, awned, awns 0.1-1.1 mm. 2n = 40.

Zoysia japonica was the first species of Zoysia introduced into cultivation in the United States, with the introduction of the cultivar 'Meyer' in the 1950s. It is the most cold-tolerant and coarsely textured of the three species that have been introduced to the Flora region, and is the only species that is currently available as seed in the United States. The other two species treated here can be established from seed, but there are currently no commercial sources for either one in the United States.

Perennial rhizome-bearing, mat-forming herb 5 - 45 cm tall Leaves: with hairless sheaths and ligules made of hairs 0.05 - 0.25 mm long. The ascending blades reach 6.5 cm long and 0.5 - 5 mm wide, are flat or have margins rolling toward the upper surface of the midvein (involute), and are hairless to soft-haired. Inflorescence: terminal, spike-like, 2.5 - 4.5 cm long, rising above the upper leaves, with the main stalk 0.8 - 6.5 cm higher than the sheath of the uppermost leaf blade. Fruit: a caryopsis. Culm: 5 - 40 cm long, with internodes 2 - 10 mm long. Spikelets: 25 to 50 per inflorescence, 2.5 - 3.4 mm long, 1 - 1.4 mm wide, egg-shaped but laterally compressed, with a 0.1 - 1.1 mm long awn, borne on a stalk 1.6 - 3.5 mm long. Glumes: unequal or usually without a lower glume. The upper glume surrounds the floret, is thin but firm or leather-like, and has an awn to 2.5 mm long. Florets: one per spikelet. Lemma: lance-shaped to linear, thin, single-veined. Palea: usually absent, thin if present.

Similar species: No information at this time.

Flowering: June to September

Habitat and ecology: Introduced from eastern Asia, this species is cultivated as turf in warmer regions and sometimes grows in cemetaries of the Chicago Region.

Occurence in the Chicago region: non-native

Notes: This species is used as turf grass in the southern United States.

Etymology: Zoysia is named after Austrian botanist Karl von Zoys (1756-1800). Japonica means Japanese.

Author: The Morton Arboretum

Plants with shallow rhizomes, forming a dense turf, growing vigorously in hot sun, but early becoming brown and dormant; lvs flat, 3-10 cm נ2-5 mm; infls 2-4 cm, arising only (or scarcely) ca 1 dm above the ground; spikelets 3-3.5 mm, pale purplish-brown; 2n=40. Native of e. Asia, cult. in warm temperate regions as a lawngrass, casually escaped mainly in the s. part of our range.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

©The New York Botanical Garden. All rights reserved. Used by permission.