Korean Perilla (Kkaennip)

At a glance

Tip for beginners: Grow two or three plants, not a row — that is plenty for a household — and mark on your calendar to check for flower spikes as nights lengthen, so you can cut them before any seed ripens

Main challenge: Keeping it from going to seed: plants flower as nights lengthen in late summer, and unchecked seed heads can produce hundreds of volunteers and spread into nearby natural areas or pasture

When to plant

• Start seeds indoors 5 weeks before your last frost.
• Direct sow outdoors 1 week after your last frost.
• Transplant outdoors 1 week after your last frost.
• First harvest about 5 weeks after transplanting.

What can go wrong

• Self-sown seedlings everywhere. Flower spikes that ripen in late summer and fall drop seed that comes up thickly the next spring. Cut spikes before seed sets and bag them rather than composting. Pull volunteers while they are small.
• Escape into natural areas and pasture. Perilla is listed as invasive in several eastern states and spreads into woodland edges, creek banks and pastures. All parts are toxic to cattle and other grazing livestock, most of all while flowering and setting seed. Do not let it go to seed near pasture or hay ground.
• Leaf production stops in late summer. Perilla flowers as nights lengthen. New leaves stop, and the remaining leaves get small and coarse. This is day length, not a problem with your care. Pick heavily through midsummer.
• Poor or no germination. Seed buried too deep, old seed, or seed roasted for cooking. Sow on the surface and cover very lightly, use fresh seed labeled for planting, and try a week or two of cold, moist storage in the fridge if germination stays poor.
• Japanese beetles and spider mites. Beetles chew ragged holes in leaves; hand-pick them early in the morning. Spider mites leave fine pale stippling and webbing in hot, dry weather; rinse leaf undersides with water and keep plants watered.
• Small, tough leaves. Usually drought stress or poor soil. Water evenly and side-dress with compost or a balanced fertilizer in midsummer.

Growing guide

Korean markets in the US sell kkaennip in tidy stacks of ten leaves, and plenty of Korean households start growing it after a summer of buying it. It earns its space: one plant picked every few days can supply leaves for ssam wraps, kkaennip kimchi and soy-pickled jangajji from early summer until frost. It is also a plant that needs a firm hand at the end of the season, because it drops seed freely and has escaped gardens across much of the eastern US.

Korean perilla and Japanese shiso are the same species, Perilla frutescens, but they are different crops. Shiso (var. crispa, which has its own page) has smaller, often ruffled leaves and a bright, sharp anise-mint flavor. Kkaennip (var. frutescens) has broad, flat, slightly fuzzy leaves that can grow as large as a hand, a heavier and earthier aroma, and seeds big enough to press for perilla oil (deulgireum) or grind into deulkkae powder. Seed catalogs sometimes describe both as tasting somewhere between mint and basil, but cooks who use both rarely swap one for the other. Buy seed labeled Korean perilla or kkaennip; seed sold for cooking may have been roasted, and roasted seed does not sprout.

Perilla is a warm-season annual, and frost kills it. Start seed indoors about 5 weeks before your last frost, pressing it into the surface of the mix and covering it very lightly, since the seed germinates better with some light. Sprouts usually appear in one to three weeks at 65 to 75°F. Set plants out 1 week after your last frost, or direct sow 1 week after your last frost once the soil has warmed. Give each plant about 12 inches in full sun or light afternoon shade, in fertile soil that stays evenly moist. Plants that dry out between waterings tend to make small, tough leaves.

Start picking once a plant has six to eight pairs of leaves, taking the larger lower leaves and leaving the growing tip. Pinching out the top when the plant is about a foot tall makes it branch, which gives you more leaves over the season. Perilla is a short-day plant: as nights lengthen in late summer, it stops putting out new leaves and turns to flower spikes, and the leaves still on the plant get smaller and coarser. Korean greenhouse growers keep leaf perilla vegetative with night lighting. In a home garden, the practical answer is to pick heavily through midsummer and accept that the leaf season winds down once flowering starts.

The real trouble starts after flowering. Each spike sets many small seeds, and a garden that lets a few plants ripen seed can have hundreds of seedlings the next spring, in beds, paths and lawn. Perilla is listed as invasive in North Carolina, Virginia, West Virginia, Tennessee and Kentucky, and it has naturalized along woodland edges, creek banks and pastures through much of the East. The whole plant is toxic to cattle and other grazing livestock, and it is most dangerous while flowering and setting seed. Cut the flower spikes before seed sets, bag them instead of composting them, and pull any volunteers while they are small. If you garden next to pasture, take that step seriously.

Pests are usually minor. Japanese beetles chew leaves where they are common, spider mites can build up in hot, dry weather, and slugs go after young seedlings. Rinse picked leaves well, stack them, and use them within a week; the plant tends to keep producing as long as you keep picking.

Harvest and keep