A perennial herb garden gives you a return on your investment for many years. The plants come back year after year with very little assistance from you. Fresh herbs are some of the first plants to emerge in spring and one of the last to succumb to frost in autumn, giving you a fresh herb season at least six months long. To get the most out of your herb garden, plant a variety of culinary herbs. Most grow quite well in as little as one square foot of space. Try these nine varieties of perennial culinary herbs: chives, garlic chives, mint, oregano, sage, sorrel, tarragon, thyme and winter savory, which are all relatively hardy and should survive winter, with a protective mulch, as far north as USDA Zones 3 or 4.
Lay out your herb garden in the shape of a circle. Use dowels or even small rocks to divide the circle into eight pieces of pie. In the very center, plant a mint.
Note: Mint is invasive and should be contained. Plant it in the center of a bottomless pot sunk into the ground with about 2 inches of the pot protruding above ground. This will contain both its roots and runners.
Put a different perennial herb into each of the eight pieces of pie. Be sure to put the taller-growing varieties, such as sorrel and tarragon, on the north side of the circle so they do not shade the other herbs.
Put an old extension ladder (not a step ladder) on the surface of the soil. Fill in the area between each step with additional soil, or sink the ladder down into the surface of the soil. Plant a different herb in each compartment. For a smaller ladder-style herb garden, cut the ladder in half or remove a few steps to make larger compartments. If you site the ladder so its length is running east to west, all of the herbs will receive equal amounts of sun, and none will shade the others during the important midday hours.
Create a perennial herb garden based on a grid that resembles a checkerboard square. A grid of 3 squares by 3 squares accommodates nine herb plants. Make sure to plant the largest growing of your chosen herb varieties along the northernmost edge of the grid so they don't shade the lower growing herbs. Larger varieties, such as sorrel and tarragon, also need to be dug up and divided every 2 to 3 years to contain their size and keep them from taking over their neighbor's space.