A knot garden is a series of plants set so that when one views them from afar, they form an illusion of patterned rope weaving in and out and around itself. This type of garden emerged during Queen Elizabeth I's reign, a relative of the 'parterre', Italian/French gardens that were arranged in decorative patterns. A knot garden is an attractive way to plant herbs for your kitchen garden, with small geometric sections of herbs forming a full Celtic style knot.
Before you drive to the local nursery, you may want to set out your garden on paper. Graph paper works well. Knot gardens are traditionally confined within a square or rectangle. Consult Celtic knot information on the Internet or in books for ideas. If you are just starting out, the Irish trinity knot makes a good first knot garden. Make sure you measure your space carefully so that you can work in scale.
Once you have your design mapped out, your next step is to figure out which herbs to include in the garden. You may already have your favorites, but consider whether they can withstand your area's climate and grow happily in the soil. Consider designing your knot garden to accommodate herb pots that can be taken inside when the weather is too harsh. You can use the pots to form the border, leaving hardier plants to form the lines of the knot.
Since some areas will be bigger than others, it's a good idea to decide which plants you will use the most. You can use these to form the loops of the knot and along the sides. See http://www.dummies.com/WileyCDA/DummiesArticle/Designing-an-Herb-Garden.id-1838.html for a good picture of a triquetra, or trinity knot, garden. Keep the garden under 5 feet across or you won't be able to get at some of your carefully planted herbs!
Most herbs grow contentedly in knot gardens. Borage, sage, rosemary, fennel, thyme, parsley, oregano, hyssop, catnip, chives, cilantro/coriander, lavender and peppermint are all herbs touted as 'hardy' which will likely thrive in well drained soil with plenty of sun.
Keep an eye on some of the more enthusiastic growers, as they might try to take over neighboring herbs. Some judicious trimming can keep the lines of your knot clean and distinct. You can also pot the entire garden, if you want to, or put decorative tiles/gravel in thin lines around each herb bed.
Knot gardens aren't just for herbs; you can also plant flowers or vegetables in the same way. Keep in mind that some plants do better together than others and plan your garden accordingly. Some plants may require that you allow for pathways inside the knot to access each bed conveniently.
Happy knotwork!
