What Is a Hyssop?

Types and Geography

• Hyssop (Hyssopus officinalis) originated in Europe but after escaping cultivation in portions of North America, it now grows wild. Giant hyssop is a hybrid form with many different types available on the market, including Firebird, Purple Haze, Tutti-Frutti and Summer Breeze. The anise hyssop is a native North American version, found in the Great Plains and portions of the Upper Midwest. The threadleaf giant hyssop grows wild in parts of New Mexico and Arizona at elevations between 5,000 and 7,000 feet, notes the Missouri Botanical Garden.

Flowers and Time Frame

• Many forms of hyssop have a long flowering window, blooming throughout summer. Types such as Hysoppus officinalis start to flower in June and continue blooming into September. Most giant hyssops wait until July to flower and continue doing so until summer ends. The flowers develop on long spikes and come in different colors. Flowers of the anise hyssop, for example, are shades of purple and lavender, while the blooms emerging on the Summer Love form of giant hyssop are purplish-red.

Size

• Hyssop species remain small enough to stay manageable in the landscape. Hyssopus officinalis grows between 18 and 24 inches, with a width up to 18 inches. Anise hyssop averages between 2 and 4 feet tall, while the threadleaf giant hyssop grows to 24 inches. Giant hyssop fails to live up to its name in terms of height, with the tallest kind being Ava, at 4 feet high. Most are in the range of 2 to 3 feet tall. Yellow giant hyssop, a species ranging from Canada to the southern U.S., grows to 6 feet.

Zones and Uses

• Yellow giant hyssop displays the best cold tolerance of the hyssops, growing into USDA Plant Hardiness Zone 2. Anise hyssop and Hyssopus officinalis tolerate the winters in zone 4. The rest of these plants start as cold as zones 5 or 6 and range into warmer zones 8 and 9. Hyssop works as a plant to attract butterflies in butterfly gardens or as a perennial for woodland gardens. Depending upon the size, hyssop is also suitable for rock gardens, perennial borders and group plantings. All hyssops feature aromatic leaves and the leaves of some, including threadleaf giant hyssop, are ingredients used to make tea.