, like delphiniums, are plants which you must choose for yourself, preferably in proud bloom at a flower show. There are many hundreds of varieties, and one which is ubiquitous one year may not be available the next, so I dare not recommend them, but I will discuss the pros and cons of growing them.
In favour is the fact that you like them. Or, indeed, adore them, as do many gardeners who grow almost no other, tending them like pedigree pets. Secondly, they are amongst the finest flowers for , not if you are making a tasteful foliage arrangement for the dming-table, but if you want something showy to decorate the parish church.
Against growing dahlias is that you may not like them, finding them gaudy (I enjoy their flamboyance myself), and the hard fact that they are tremendously troublesome to grow – not difficult, but time-consuming.
are tuberous plants which come to us from Mexico, and were named after a Swedish botanist, Andreas Dahl, who worked on them in Madrid in the eighteenth century. They are divided officially into a number of , Single-Flowered, Collerette, Water-lily, Pompon, Cactus and others, but for practical purposes there are two kinds, small dahlias up to 2 feet (60 cm) in height for bedding, usually grown as from , and taller dahlias, up to 5 feet (1.5 m), for borders, which are perennial, but not hardy. Some gardeners grow these in the mixed border, where they are splendid for taking over in late summer after the early perennials, but others prefer to grow them in beds dedicated to dahlias only. The flowers can be enormous, up to 12 inches (30 cm) across.
Dahlias come in every conceivable colour except true blue. A few have dark foliage, instead of the usual bright green, and when I asked four first-rate gardeners, not specialists, to name their favourite dahlia, three chose ‘Bishop of Llandaff, a blood-red peony-flowered variety 3 feet (90 cm) high, notable for its purple foliage.
The cultivation of dahlias is a year-round affair. They like full sun, good, masses of food and a great deal of water. To skate briefly over the growing programme, the work starts in autumn, when you must dig the beds and work in rotted manure. In spring, work over the beds and sprinkle in some balanced fertilizer. Plant the tubers in late spring or early summer, according to your climate, giving each plant a stake, from 12 to 36 inches (30 to 90 cm) apart, depending on size. From then on, watch the plants, mulch, water and disbud, spray for , trap slugs and snails, and catch earwigs as best you can. (Canes topped by inverted flowerpots set as traps for earwigs are not a beautiful sight as you take a stroll round the garden in the twilight.) Enjoy the flowers from late summer until the first frost, when you lift the tubers and store them for next year. Dahlias are a madman’s obsession, but gardening would not be the fun it is without our fanatics.