Perilla frutescens aka Perilla

Perilla frutescens is a leafy herb in the mint family. Its common names include shiso, perilla, and beefsteak plant. It comes from Asia, from the Himalayas to Southeast Asia. Its wider range includes China, Korea, Japan, and the Russian Far East. Gardeners grow it as an annual for food and foliage. It has also spread into the eastern United States and Canada.

Plants grow fast and form upright, bushy clumps. Garden plants reach 1–3 feet [0.30–0.91 metres] tall. They spread to about 1.5 feet [0.46 metres] wide. Some reach 4 feet [1.22 metres]; a broader account records 6.6 feet [2 metres]. The square stems have four grooves and short hairs. Stems may be green or purple and have a scent. Pairs of broad, egg-shaped leaves grow along them. The leaves have wrinkled surfaces and toothed edges. They can be green, purple, or red, with a strong scent when crushed.

Small white flowers appear from August to October. Each flower has two lips and a bell-like shape. Flowers grow in upright spikes at stem tips and leaf joints. The spikes can reach about 0.33 feet [0.10 metres] long. Bees pollinate the flowers, and the plant attracts butterflies. The fruit is a tiny gray-brown nutlet with a net-like surface. Wind spreads the seeds, and plants can sow themselves in large numbers.

Full sun gives the best growth, though plants accept some shade. They prefer loose soil with good drainage and plenty of organic matter. Moist soil supports good growth, but plants also withstand dry soil. They resist heat and drought. One growing account gives a preferred soil pH of 5.5–6. The plant is frost tender, with winter hardiness in USDA zones 10–11. In colder regions, gardeners grow it for one season. Pinching stem tips helps keep plants compact and bushy. Seeds can start indoors before the last frost or outdoors afterward.

Gardeners use perilla in herb beds, borders, pots, and window boxes. People eat the leaves in salads or use them for flavor. They also harvest the seeds for food. Eastern Asian traditions use the plant in medicine, and it supplies oil. Neither major insect pests nor major diseases are reported. Its spread poses a greater concern than these problems. Several eastern states list it as invasive, including North Carolina. It can crowd out native plants in disturbed ground. Removing spent flowers helps limit seed spread. Avoid sites where it could escape into nearby natural areas. Despite its food uses, it can poison cattle and horses. Reported effects include severe breathing problems and death.