By the 16th century in England, the “knot garden�?had become a popular design for a formal herb planting, with a rectangular bed laid out in an intricate geometrical pattern. Inside the interlacing lines of herbs or miniature box (Buxus) hedges, small beds or compartments were each planted with a single variety of herb, often selected for its ornamental foliage.

Formal Design Elements
The intricate knot garden is still a beautiful way to grow herbs, but today most home gardeners find the heavy maintenance required to keep it weeded, pruned and looking good too formidable and time-consuming. However, if a formal herb garden fits with your house and landscape, you can incorporate some traditional design elements that will lend the appeal of a formal appearance without the high maintenance.

The most basic characteristic of all formal herb gardens is their use of a “focal point,�?something that draws the eye to the center of the design. This center point is typically an architectural feature, such as a sundial, pedestal, column, birdbath, fountain or a decorative or distinctive pot. When planning an herb garden, start with this central focal point and work outward, defining beds with radiating paths that divide the garden into quarters (for a square or rectangle) or into pie-shaped sections for a circle or wheel design (see illustrations). The point of these formal designs is to set off each individual herb, rather than merging different types into an indistinct hedge or border.

Many kinds of perennial plants �?both herbaceous and woody �?can be used for edging in the formal herb garden, from shrubs such as southernwood (Artemisia abrotanum) and various evergreens to low ground covers such as creeping thyme (Thymus praecox). Another idea, especially if your soil is heavy or clayey, is to grow herbs in a number of neatly sided raised beds, organized in a geometrical pattern.

Paths or edgings made of bricks or other paving materials such as Belgian blocks add a nice formality to the herb garden. Paved paths provide easy access to the beds for maintenance and serve as walkways �?plus, they are easier to maintain than traditional boxwood hedges. Another benefit of bricks is that they soak up and retain the warmth of the sun, something that is appreciated, especially in the cooler climates, by heat-loving Mediterranean herbs.

Informal Garden Ideas
Formal gardens are beautiful, but many people prefer to incorporate herbs into their existing garden spaces, among either ornamental or edible plants. Annual herbs such as basil and summer savory are natural partners for tomatoes and beans in the vegetable garden, while purple-leaved basil or calendula make good choices in an annual or mixed flower bed. Perennial herbs such as creeping thyme feel right at home in a rock garden, while taller plants such as hyssop (Hyssopus officinalis) and silvery wormwood (Artemisia absinthium) fit nicely into an ornamental border.

Another way of using herbs in the landscape is to combine fragrant plants to make a “scented garden.�?First, find a sunny spot where you might enjoy sitting with your morning cup of coffee, or in the evening after dinner. Reserve a spot in or next to the garden for a wooden garden bench, or a table and chairs for outdoor dining and entertaining. Then select herbs of various heights and growing habits, whose scents will turn this spot into a pleasant area for reading, socializing, or private meditation.

So many herbs have a delightful fragrance that it’s hard to limit yourself to just a few. Some excellent choices for the scented garden include English lavender (Lavandula angustifolia), lemon balm (Melissa officinalis), all kinds of mints, oregano, rosemary, scented geraniums (Pelargonium spp.), costmary (Chrysanthemum balsamita), and dame’s rocket (Hesperis matronalis), whose flowers release a delightful clovelike aroma in the evening. Plant fragrant ground covers such as creeping thyme (Thymus praecox) and Roman chamomile (Chamaemelum nobile), perhaps in gaps between flagstones or other large, flat paving stones set around the area.

Gardeners who are interested in naturalizing herbs in a somewhat wilder setting can select from a wide range of hardy plant species. Certain herbs are aggressive and vigorous, fitting better into the landscape at large than in a mixed bed or border, where they can quickly crowd out other plants. Examples include various mints (Mentha spp.), elecampane (Inula helenium), comfrey (Symphytum caucasicum), tansy (Tanacetum vulgare), and soapwort or bouncing-bet (Saponaria officinalis). Look around your property and see what kinds of sites and soils you have; you’re sure to find niches that offer the perfect conditions for some of these wilder herbs to thrive and spread.

Growing Herbs in Containers
Growing different types of herbs in containers is a great idea for several reasons. First of all, you can grow tender perennials like rosemary and flowering sages all year long, bringing the pots indoors as days shorten and temperatures dip in the fall. Secondly, growing in containers gives you the flexibility to move plants around outside and display them to best effect. Containers also are a boon for gardeners who have poorly drained soil or limited growing space.

The soil you use in containers should be well-drained; regular potting soil amended with perlite and vermiculite will suit most plants. As with other plants in containers, herbs require regular watering and fertilization throughout the growing season. Plants like rosemary can tolerate fairly dry soil between waterings, but other herbs with broader leaves need more attention to watering when grown in pots. Adding finished compost or peat moss to the soil mix when you are potting plants will help the soil retain moisture.

During the outdoor growing season most potted herbs can be fertilized as frequently as once a week. Use a liquid fish or seaweed emulsion or a complete liquid fertilizer. Once you bring plants inside for the winter, they require much less fertilization; once or twice a month is sufficient. Especially after plants are inside, it’s important to practice “flush watering�?regularly; in other words, keep adding liquid until you see water running out of the bottom hole in the pot and into the tray beneath. This prevents fertilizer salts from building up in the soil.

Herb plants that can live for several years in pots include rosemary, lemon verbena, bay laurel and scented geraniums. Check plants periodically to see whether they need to be repotted into a larger container.

During the winter, the best place for herbs is inside the house next to a cool, sunny window, where they can get about three or four hours of direct sunlight every day. Conditions inside most houses during the winter months are dry, so mist plants or place them in trays on top of watered pebbles to increase the humidity level.

Plants that you bring inside for the winter invariably experience some insect problems. This is frequently due to the stress of being moved into an indoor environment and new growing conditions. The best way to minimize this stress is to dig and pot up plants at least a couple of weeks before the first frost, then acclimate them gradually to indoor conditions, perhaps by moving them to a porch or breezeway (a reverse process to the hardening-off that you do in the spring with plants started indoors). Watch the plants closely for the first few weeks inside, and pamper them by providing plenty of water and misting them.

Even given this tender loving care, some herbs will become infested with insects. If you shake a plant and see a cloud of whiteflies, it’s a good idea to set the plant in the shower briefly and wash the insects off the leaves. Then spray the plant with an insecticidal soap or hot pepper wax. Follow label instructions and repeat treatments as needed. Some long-lived herbs can be pruned and trained into interesting topiary shapes or ball-headed “standards,�?which makes them valuable as formal accents on a patio, entrance, or walkway during the summer, and as houseplants during the cooler months of the year.