The sweet, anise-flavored leaf of French tarragon (Artemisia dracunculus) is a key ingredient in béarnaise sauce and fines herbs. It also makes a delicious addition to egg dishes, seafood, salad dressing, vegetables, and poultry. You will find plants of this hardy perennial for sale, but not seeds because the plants seldom produce viable seed. If you find seed for sale, it's probably Russian tarragon (A. dracunculoides), a related species with what most cooks consider an inferior flavor. (Grow French and Russian species side by side, and decide for yourself!)
French tarragon is hardy to USDA zone 5, or to zone 4b with winter protection. It grows well in full sun or partial shade, and needs well-drained soil. Purchase plants propagated from stem tip or root cuttings, or from crown divisions. Space plants about 2 to 3 feet apart to give them room to spread.
Harvest regularly or prune plants to a height of 2 feet to prevent flowering and keep plants neat. In central and northern states, water deeply and spread mulch in late fall to protect the roots over the winter. Divide the plants every 3 to 4 years to keep them healthy and vigorous. Each established plant can yield 2 or 3 divisions.
Harvest and Storage
Harvest leaves in early to midsummer when they contain the most essential oil. Use leaves fresh or freeze them in airtight bags for later use. Steeping tarragon sprigs in vinegar is another popular preservation method. If you dry tarragon, you may have to use more than called for in recipies, as it loses its flavorful essential oils during drying and storage.