Take cuttings in autumn. Set plants 18 to 24 inches apart. Roots spread laterally rather than vertically, so plants must be cultivated carefully and mulch must be provided over the winter for frost protection. Plants should be divided every two or three years to reinvigorate growth and flavor. Tarragon plants rarely produce viable seed.
Harvesting can begin six to eight weeks after setting out.
Handle leaves gently because they bruise easily. When leaves begin to yellow, harvest the whole top, cutting back to about three inches above the ground. Fruit is four tiny seedlike nutlets. Thyme is one of the fines herbes and tastes delicately green with a faint clove aftertaste. Leaves and sprigs are used in salads as garnishes and clam chowder, stuffing, pates, sausages, stews, soups, gravies, stocks, bread, herbed butters and mayonnaise, flavored vinegars, pickles and mustard.