Keep the plants well-watered during hot weather. Start Japanese hop from seed sown directly outdoors. Space the seed about 18 inches apart at the base of a support. Once established, the plants will reseed themselves. Propagate common hop by root division or from cuttings of new growth taken in the spring, preferably from female rootstock.
Plants die down in winter, but fast-growing shoots appear again in spring.
Protect the roots with a mulch over the winter months. Harvest the flowers in autumn, when tinged with yellow. Medicinal Uses Avoid the use of hop if depression or impotence is a problem. A tincture or infusion prepared from the flowers of common hop is used to treat insomnia and headaches, and may also improve digestion. A pillow stuffed with dried flowers is believed to induce restful sleep.