Gardens: dianthus, prettiest of pinks

Just for frills: Dianthus carthusianorum. Photograph: Alamy

It all began with a Sunday afternoon trip to Special Plants in Wiltshire. Being close by, it is an easy excursion. I can even walk if I am committed to the fact that I will probably have to drive back later to collect my booty. This time it was Dianthus ‘Elizabethan’ that broke my resolve. You can imagine the flowers appearing as a detail in a Dutch old master painting: pale chalk white with rounded edges to the petals, just outlined in carmine pink and an almost black blotch to the centre.

Four years on, I know the plant much better and forgive it its ranginess. Out of season it is easy to think it might not be worth it, but come early summer it galvanises. The long-stemmed flowers spill over their neighbours, and the scent of cloves is enough to perfume a room if you pick enough for a posy. ‘Elizabethan’ was joined quite quickly by about 10 varieties that I picked from the Allwoods website. I chose single- flowered varieties and have by a process of elimination or failure reduced the little trial to a handful.

The Cheddar pink, our native dianthus of limestone outcrops, dwindled and died on me without flowering. Despite my inclusion of sharp grit in the compost for drainage and keeping the pots in bright, dry positions, our Somerset moisture proved too much. Dianthus plumarius is diminutive but delightful with its fringed petals. I have jettisoned a number that were just too pretty. They would have looked lovely in a cottagey garden but I wanted the pinks either to pack a punch with bright, clear colour or to be a little mysterious neon.

I have grown ‘Neon Star’ in a pot for 10 years. The blue-green foliage fills the pot in a perfect dome when not in flower, and then erupts in short-stemmed flowers. They are brighter than a campion, eye-catching and perfumed. A potful will flower for a good six weeks.

Though not such a strong grower, ‘Solomon’ has the darkest ruby red base and frilled mauve fringes. ‘Unique’ has a plum base and bright pink flares, two to each petal.

The biennial Dianthus barbatus, or Sweet William, is easily raised from seed like wallflowers, sown direct in June and then transplanted in the autumn. They last a good three years. I use ‘Sooty’ through the filigree foliage of Anthriscus ‘Raven’s Wing’. Cut them back immediately after flowering and you might get a diminished but welcome second crop in the second half of the summer.

I am hoping the perennial Dianthus cruentus seeds about in my gravel garden. The tight green rosette needs light to the base, so grow it with low groundcovers such as Acaena. The flowers are bunched together tightly, each a dramatic red with dark calyxes. The long stems of Dianthus carthusianorum are finer still. To my complete delight, I saw these growing in a sunny south-facing meadow at the Inner Temple gardens in London. I already have seedlings in my frame ready and waiting for release.