When selecting plants for a formal herb garden, consider the growth habits and mature sizes of the plants. Place low creepers, like thyme and chamomile, on opposite path edges to complement each other. Put more aggressive herbs, like mints and lemon balm, in pots either above or below the ground.
Most herbs used for culinary purposes won't be allowed to flower early in the season. So focus on texture and foliage color to bring a sense of fullness to your herb garden design.
Make sure all the plants can be accessed, both for harvesting and maintenance without walking into the beds. The paths should be at least 3' wide, for easy walking. Since this is a formal garden, the paths can be paved or mulched, to provide the axis for the garden.
The garden design shown here contains 20 different herb plants. Most of these plants will flower at some point in the season, but there is plenty of variety with just the plant shapes and textures. The sprawlers are kept to a minimum, to retain a somewhat formal feel. You can, of course, improvise any way that suits you.
The color scheme is another unifying element that adds to the formality. It makes use of the complementary colors combos of purple/yellow and blue/orange. If the orange of the calendula and nasturtiums is too bold for you, you can always substitute one of the paler yellow varieties or the pink variety of calendula.
The center of a formal herb garden is usually the focal point. Even though there is formality, the focal point is a chance to you to show your gardening personality. It could be a large herb plant, such as a sweet bay tree or a large potted rosemary. Many gardeners like to put a garden ornament in the center of their herb gardens, like a bird bath, either as a bath or as a planter. Another popular feature is placing a sun dial in a small center bed and surrounding it with thyme plants. Whimsy is permitted in a formal herb garden.
The following pages will go into specifics on the plants used and listed here: