Panicum repens aka Couch Panicum

Panicum repens, or torpedo grass, belongs to the grass family, Poaceae. This perennial grows from a spreading network of underground rhizomes. Its native range spans the Old World tropics and subtropics. It reaches from southern Europe through Africa and Asia to Indonesia. The range also includes southeast China and the Philippines. It grows beside lakes, dams, swamps, and brackish shores. It also grows as a weed among perennial plantation crops.

Its tough stems stand upright or lean along the ground. The source lists a height of about 2 feet [0.6 metres]. Its fuller account gives 1–4.1 feet [0.3–1.25 metres]. Fast growth lets the grass form broad, dense stands. These stands can dominate the ground and crowd out native plants. Rhizomes drive much of this spread beneath the soil. Wind carries its pollen, but the evidence gives no flowering season.

This grass suits warm conditions and has little cold tolerance. Long spells of frost can kill it. It grows best with daytime temperatures of 18–26°C. The source gives a wider tolerated range of 13–35°C. Full sun suits it best, though it accepts light shade. It favours sandy soil but also grows in moist, heavy soil. Most moist or wet soils with moderate fertility can support it. Its preferred soil pH is 4.5–6.2, though it tolerates 4–7.7.

People grow torpedo grass to hold loose soil in place. Its dense cover helps protect unstable ground from erosion. Yet the same growth creates a risk for nearby native plants. Its landscape value therefore comes with a clear weed problem. The source reports no known edible or medicinal uses. It also lists no known hazards. That statement does not establish food safety or safety for pets.

Seed and division both provide ways to raise new plants. Sow seed on the surface or beneath a thin soil cover. Keep the mix moist and place it in sun. Fresh seed may need a dormant period before it sprouts. Buds occur along the rhizomes, but many remain dormant. Breaking the rhizomes into pieces can wake these buds. Pieces about 0.16 feet [0.05 metres] long can produce new plants. These small pieces can soon establish fresh growth.