Plant hyssop from seed, or propagate from cuttings or by dividing other plants. Hyssop prefers a sunny location but tolerates some shade. It grows in poor soil but does best in alkaline soil that drains well. Plants can be trimmed to form a low-growing hedge and grow in containers or rock gardens.
Hyssop is an evergreen and you should not trim it for the dormant season. Wait until the beginning of growing season and trim the perennial to the ground. Trim the plant to maintain its shape until frost.
If you are planting hyssop from seed, start the plants in a cold frame, and transfer them to pots. Keep the pots in a greenhouse for the first winter before transferring them to the ground. If you are propagating from existing plants, take cuttings of half-ripe wood, and start them in a cold frame. Transfer all plants after the danger of frost passes.
Hyssop attracts beneficial insects and butterflies. It is useful for cut-flower arrangements and is not aggressive, although it may self-seed and plants grow from 1 to 3 feet in diameter and 1 to 2 feet tall. You may need to replace older plants after a few growing seasons.