Hyssop Growing Guide

Hyssop prefers full sun. It may grow in partial shade but will get lanky without enough sunlight. Hyssop requires well-draining soil on the dry/loamy side with a pH of 6.5 to 8.0. If transplanting, sow seed indoors 8 to 10 weeks before the last frost. Transplant hyssop outdoors the last frost. Start seed in flats under fluorescent grow lights. Occasional pruning can help encourage the plant to bloom and keep the plant looking its best. It grows best in USDA Hardiness Zones 3-8. Plants reach maturity at about 90 days.

Start seeds anytime from late winter to late summer with a lightweight soil mix. Keep the soil moist but not soggy. As seedlings appear, gradually expose them to direct light. When the plants are large enough to handle outdoor conditions. When danger of frost is over, transplant to the garden 1 to 3 feet apart. Sow seed outdoors after the last spring frost.

Hyssop is also a key ingredient in Chartreuse, a green-tinted liquor made by Carthusian monks since 1737.

Harvest hyssop leaves as needed before the plant flowers. Pick flowers when the blooms are three-quarters open. Gather flowers in the morning when the dew has dried. Snip off portions of the stalk when harvesting a small number of leaves for immediate use then strip the leaves from the stem. Cut whole branches for drying leaves or flowers. Do not wash the leaves or aromatic oils will be lost.

Fresh hyssop leaves can be kept in the refrigerator for a few days. Wrap leaves in a damp paper towel and place them inside a perforated plastic bag. For drying, hang whole branches upside down to air dry. Dry flowers and leaves on a screen in a well-ventilated shaded warm place for 2 to 5 days. Do not let leaves over dry; they will be less flavorful. Store dry hyssop leaves and flowers in an airtight container.