Salvia is one of the largest of all the plant genera with almost a thousand species and a colour range of flowers that is broad and exciting. It sits in the family Lamiaceae along with many of the aromatic herbs including the much-valued sage plant, Salvia officinalis. But while the common sage is prized for its culinary merits, its flowers are not as exciting as many of the other salvia species. Among the first to have been grown in British gardens, recorded as early as the mid 1700’s, is Salvia nemorosa, a fine clump-forming species and of all its cultivars ‘Ostfriesland’ is most spectacular. It is fully hardy and has lance-shaped leaves and violet flowers with pinkish bracts that remain and look attractive long after the flowers have faded. It is a fairly compact plant with an eventual height if about 45cm and so should be grown towards the front of a bed or border. The taller, but less hardy, Salvia patens has the most striking royal blue flowers and perhaps this is why it is the best known salvia amongst gardeners. These delightful flowers are hooded and are borne in pairs in whorls along the flower stalk. If you want a showier version then choose S. patens ‘Guanajuato’ which bears much larger flowers of the same true blue. It can overwinter successfully in milder areas in Britain, but elsewhere it will succumb to the cold, so it is best to lift the tuberous roots and protect them indoors until the following spring. You may want to increase your stock by splitting them. The blackest flowers appear on the exquisite yet slightly sinister looking Salvia discolor, a tender species which needs to be grown at the border’s edge to enable you to get a good look at the deep indigo flowers for the stems droop under their weight. For the most wonderful woolly foliage in a bright silver you cannot do better than Salvia argentea. This plant forms a rosette of these curious leaves and bears mauve-flecked, white flowers in high summer. It is very important to remove the spent flower stems at their base to stop the plant from setting seed and dying, doing so this will often encourage the plant to throw up a second helping of flowers. All salvias perform best in the sun, so it is best to grow them in an open situation where they will get plenty of light in free-draining soil and give them a drink at the driest times.
Herbs have been grown and eaten for much of recorded history, but many are also wonderfully decorative with textured foliage and pleasing flower forms and colours, and so will enhance any flower garden. Most herbs enjoy the sunshine and with our increasing annual temperatures it is worth considering not only growing some of the common herbs but, perhaps experimenting with some of the less usual, tender ones. Of course, to some extent it should be your palate that dictates which plants to grow as there is little point in filling a garden with herbs which you will simply never pick and use in the kitchen, unless you want them purely for their aesthetic value.
Whether you decide to grow herbs for cooking in a designated herb garden, or mixed throughout your existing garden or even in pots, it is still worth making the overall effect attractive by combining plants well. The style of any herb garden depends upon personal taste; some may choose to grow herbs in a formal manner between box or lavender hedges, as in a parterre, many may opt to grow their plants in a wilder, more natural way, while others may choose the allotment style, with plants in regimented rows, but the same principles of horticulture apply whatever the style. For example, thuggish plants, like mints, must still be contained and tall plants, Angelica for example, should not be allowed to block the light from smaller plants. Often, herbs in small pots are bought on a whim and planted in a cursory way so that the result is an entirely haphazard garden that shows a lack of regard for design and for the growth habit of the chosen plants.
Always plan a garden on paper before planting, taking into account the height and spread of plants, the colour of the flowers and foliage and also the times when they are at their best; by doing so you can decide which will look good together and where to place them. Personal taste affects these decisions; one person may choose to have perhaps a bronze fennel towards the front of a bed or border so that other plants behind may be seen through its fuzz of foliage, yet others may want to set the fennel back so it does not obscure smaller plants. It is the process of jotting down shapes and plant names on a planting plan that makes you consider these things.
Site a herb garden in a sunny location. It is often a good idea to have it close to the house for convenience for while in summer it is pleasant to wander to the herb garden to snip some rosemary, it is a very different matter on a cold, dark and wet January evening. First, plant shrubs that will provide a bit of structure, the bones of a garden if you like, the flesh, in the form of perennials and annuals, can be added later. Normally these will be lavenders, rosemary or bay, which are indeed fine plants, but you could try experimenting a little with some Myrtle, Myrtus communis or Chilean Guava, Ugni molinae both of which are evergreen and have pretty, white flowers followed by edible berries. Or perhaps try growing Luma apiculata, another evergreen, for its tasty leaves that add flavour to stews. And when it comes to filling in around the shrubs with fleshier plants it is also worth adding some of the more unusual herbs to the mix, for example, Lemon Grass, Cymbopogon citratus for its lemon-scented leaves. Among the annuals there is Purple Shiso, Perilla frutesens var, purpurascens, which has beautiful, crinkled purple leaves that are wonderful in stir-fries or Coriander, Coriandrum sativum, which will certainly enjoy the warmer summers we seem to be experiencing. Whether your herb garden is traditional, wild or simply a huddle of pots outside your door, room can always be made for a few newcomers to entice the taste buds and stretch your horticultural talents a little.