Traditionally, herb gardens were laid out in complex geometric designs, with formal symmetric beds often edged in Box (Buxus sempervirens) with its slow growing nature that lends itself to neat clipping. A mixture of plants were grown for differing uses from medicinal to culinary, scent or simply for decoration. So firstly decide why you want to grow herbs.
If you want to grow large quantities of Basil to make pesto or to harvest Lavender for drying, then the number of plants you need will impact your design. Choose your location, preferably sunny and close to the house for easy access but the site need not be totally flat. The soil type preferred is well drained with a slightly alkaline soil.
How to design….
Do it on paper first. Measure the site to scale and draw it up. Design your pattern based on 4 or 6 beds with gravel or stone paths in between. Keep it simple and make sure you allow sufficient space for the width of hedging; stepping stones can be used in larger beds to make access easier. Remember the different angles that the garden will be viewed from - both ground floor and upstairs.
Choose your plants…
Choose your edging – it needs to look good and tidy in winter and give structure. Because of the disease ‘Box blight’, some alternatives to Box are now being used such as Teucrium (as used at Highgrove) and Ilex crenata – a small leaved Holly that can be clipped in the same way. Lavender, Rosemary and Hyssop can also be used as long as they are clipped properly.
Choose your single key plants to give architectural structure such as clipped Box cones or Angelica. Choose decorative shrubs like Rosemary, Lavender and Sage. Finally your perennials, biennials and annuals – such as Sorrel, Fennel, Thyme; group your plants using 3-5 of a variety. Build up your collection of plants into a design, checking the height and spread. Consider the shapes of the leaves as well to give contrast.