How to grow Dianthus, and what the best varieties are

At 5:30am I part the living room curtains. On cue, Jamie pulls up to the curb, a dismantled red road bike crammed into his back seat. He gives a smiley thumbs-up.

In the gloom, we transfer bike and bags into my family estate car while I run through a checklist of twos: two tents, two sleeping bags, two bikes, two passports. I run up to kiss a sleeping wife and baby and return with a near-forgotten bottle of Côtes du Rhône.

Disaster averted, we head for Dover. This wasn’t the original plan. The intended trip to Europe was a three-month affair, in which my wife and I would meander the great landscapes of the Continent, introducing our new recruit to wonderful European wild flowers: an idea formulated last summer amid the early weeks of pregnancy, under canvas up a Swiss mountain.

We’d resume 2019’s summer flower tramp through Europe, venturing further south and east. The turbulence of Covid-19 and the uncertainty of international lockdown measures, however, had, for now at least, whittled this idyllic expedition down to an overnight round-trip to Normandy with a friend. But Jamie is good company, can fix a bike in a bind, and, it turns out, ace a road snack and an excursion-appropriate historical podcast.

At the white cliffs we’re funnelled smoothly on to a waiting DFDS ferry, and stand on deck, faces mask-clad, watching the receding coastline. My mood is jubilant. Having spent last year rambling glorious terrain – from arid Arizona to alpine Italy – it feels momentous just to be crossing the Channel.

The itinerary is this: arrive in Calais with the morning still young; make haste for the Cotentin Peninsula and on to the grassy dunes of Manche. Erect tents, saddle bikes, and set out for coastal flowers.

Though late in the season, a French excursion will have lots to offer a gardener unshackled from London. It promises trefoils and tansies, purple mallows and perennial peas; fields of salvia and chicory – and no doubt some surprises along the Gulf-warmed coast. Above all, I have hopes of running into a plant that had evaded last summer’s haul: the wild carnation.

Research suggested Normandy as a hotspot for this diminutive yet outlandishly pretty, frilly-edged wild flower – believed to have been first introduced to England by the Normans.

Departing Calais, we follow verges packed with honey clover and nodding evening primrose towards the motorway leading south. It’s a brightish morning, though clouds loom ahead. Jamie hands me a Percy Pig and cues up episode one of Lars Brownworth’s Norman Centuries: Viking Rollo, the first Duke of Normandy.

By mid afternoon we know our Robert the Magnificent from our William the Conqueror, though with the clouds now threatening rain it’s a rush to set up tents, hammering pegs into damp sand below a bank of feathery French tamarisk.

Lodgings in order, we ride out along the coastal path assailed by a gathering sea wind. It takes Jamie’s hat, and then mine, landing them among the scattered pinks of thistle, thrift and lucerne.

Within minutes it’s apparent we ought to have waited-out the downpour, but the flowers are stacking up nicely: swaying white umbellifers, rosy maritime calystegia (that most inoffensive of bindweeds) and sea holly (Eryngium maritimum) bluer than any I’ve encountered at home. The plant is prolific, anchored to the shifting dunes by 1.5m taproots.

An hour later I’m enraptured by yet more gorgeous examples, flowering among windswept bunny grass and creeping restharrow. Jamie the Forbearing dutifully dismounts and photographs the blustery panorama. Around us, little white snails shelter from the driving rain in thickets of mustard-yellow rocket. I chew over our predicament, and a salty rocket leaf, and suggest we call it a night.

Before bed, back at camp, we split the Côtes du Rhône under the raised car boot. Encouragingly, evening light has begun perforating the clouds, suggestive of sunnier skies.

Sure enough, the next morning we wake to a far brighter, quintessentially mild rural France, and by 6.30am are bombing it back along the coast – taking the road this time – to pick up where we left off. Shimmering poplars edge glaucous onion fields; sweet woodsmoke perfumes the sea air, now alive with swallows, and there’s a man on a bicycle carrying a baguette underarm. Things are certainly looking up.

I’ll fast forward this merry travelogue to a few hours on, our moment of triumph at the welcome sight of wild carnations. Stopping beside a carpet of mossy thyme, metres from the beach, I am drawn to a clutch of tall sea thrift and then the telltale blue-green thatch of dianthus foliage.

Huzzah! We circle around and there it is: a radiant pink (Dianthus gallicus in this case), its finely serrated petals inconceivably delicate for such a severe environment. A dozen more are growing close by, the last of the summer’s offering.

D. gallicus (the ‘Jersey pink’) is closely related to D. caryophyllus, the wild Eurasian ancestor of most familiar and extolled carnations. As garden plants, pinks have seen a resurgence in popularity, deployed by contemporary garden designers for their resistance to drought. D. carthusianorum combines height (50-60cm) with magenta blooms; D. deltoides ‘Albus’ is a dainty white, while D. cruentus blazes brilliant red.

These fragrant, five-petalled, single-flowering forms, in contrast to the blowsier doubles (although these are making a similar comeback in the cut-flower arena), possess an unrivalled elegance. If lightly clipped after flowering, their semi-evergreen foliage provides a weed-suppressing mat and potential secondary blooms. All perform best in free-draining soil with a light, protective mulch.

On the ferry home Jamie shows me a photo of his balcony planter: three plants, one floriferous. “That’s a carnation!” I say – his eyebrows raise. “Well, a sweet william; but still a dianthus!” A quick phone scroll reveals that sweet william (D. barbatus) may have been named after William the Conqueror; a most fitting epilogue to our fleeting Norman conquest.

Matt Collins is head gardener at the Garden Museum in London. Follow Matt on Instagram 
@museum_gardener.

How to grow 

Plant

• Dianthus prefer full sun, though with a little protection from the wind. A loamy to free-draining soil is best, with lots of organic matter dug in. An airy mulch will help protect plants through cold winters – avoid using heavier material, e.g. horse manure or damp bark chip.

Care

• Trim lightly after flowering to encourage a second flush of flowers. This will also keep foliage tight and compact. Propagate by taking softwood cuttings.

Companions

• Grow with light grasses, 
e.g. Stipa tenuissima, or in a gravel scheme among cistus, Cephalaria gigantea and, of course, eryngium. See right for Dianthus cruentus used by Cleve West at Chelsea 2011.

Varieties to try 

Dianthus gallicus 'Gallic Pink'

Dianthus cruentus

Dianthus carthusianorum