You can store fresh perilla leaves in the freezer, but be careful not to leave them too long. Preservation method:

Picked or purchased the whole bunch of perilla put into a cup or bowl filled with water, soak the stem end in the water, wrap it with plastic wrap along with the container, and then put the whole thing into the refrigerator to freeze.

If the amount is small, you can wash and dry the leaves, wrap them separately in plastic wrap and then put them in a plastic box, and keep them refrigerated for a week or frozen for 1 to 2 months. It is difficult to keep perilla leaves fresh for too long, and they will release an astringent flavor over time, so it is recommended to process them as soon as possible.

In summer, the temperature of water is always much lower than that of air, and a lot of water is used to preserve things by wrapping it in a clean plastic bag and putting it in water, pressing it with a stone so that it sinks to the bottom.

Expanded Information:

Purslane is an erect annual herb. The stem is 0.3-2 meters tall, green or purple, obtusely 4-angled, 4-sulcate, densely villous. Leaves broadly ovate or rounded, 7-13 cm long, 4.5-10 cm wide, apex mucronate or acute, base rounded or broadly cuneate, margin coarsely serrate above the base, membranous or herbaceous, green or purple on both surfaces, or purple only below, sparsely pilose above, adnate pilose below, lateral veins 7-8 pairs, slightly closer together in the lower part, obliquely ascending, and with the midrib faintly raised above and distinctly raised below, slightly lighter in color Petiole 3-5 cm long, dorsoventrally flattened, densely villous.

Verticillasters 2-flowered, forming terminal and axillary racemes 1.5-15 cm long, densely villous, biased to one side; bracts broadly ovoid or suborbicular, ca. 4 mm wide by 4 mm long, apex mucronate, externally reddish-brown glandular punctate, glabrous, margin membranous; pedicels 1.5 mm long, densely pilose. Calyx campanulate, 10-veined, ca. 3 mm long, straight, villous proximally, interspersed with yellow glandular dots, sparsely pilose ring on inner throat, enlarged when fruiting, to 1.1 cm long, flat or pendulous, swollen on one side at base, calyx limb 2-lipped, upper lip broad, 3-toothed, middle tooth smaller, lower lip slightly longer than upper lip, 2-toothed, teeth lanceolate.

Baidu Encyclopedia - Perilla