A ringing endorsement of the bell-flowered campanula

Image of Robin Lane Fox

The summer has now passed half-time but it has been wondrously good for English gardens. The evenings have been cool but usually without rain. Such sunlight as we have had has been broken by light cloud. The ground is not too dry. In the hot 1990s I began to wonder if the mild summers of my gardening youth were a mirage. This one has been exceeding all those dreams. It followed a late spring which left wisteria, peonies, lupins and so much else to come out all at once with the usual June favourites. If you have not marvelled at a garden yet this year, I pity you. It is the best year in the past 30.

Down at soil level I have been scratching away, especially in those charmed hours between 7.30 and 10 each night. We are deep in the season of dead-heading, immortalised by Sissinghurst’s owner, Vita Sackville-West. “Dead-heading the roses on a summer’s evening,” she wrote, “is an occupation that carries us back into a calmer age and a different century ... There is no sound except the hoot of an owl, and the rhythmic snip-snip of our secateurs.” Try it and you will agree. Dead-heading is the one type of cut that inarguably works. It tidies the plants and encourages a second show of flowers on so many of them. It is crucial not just for roses but for all bedding plants, the only way to keep them going into October.

In these cool weeks it has also been possible to plant and replant late and to get after the roots of persistent weeds. Much of my work here has concerned the stars of the next two weeks, the bell-flowered campanulas. Through them it illustrates so much that is fun about modern gardening and why it is not standing still.

Campanula Samantha

My main campanula problem may well ring a mental bell. I have managed to buy and import my own worst enemy, paying good money for it in good faith. Back in the mild summers of my youth I used to read of the ultimate menace among plants, bemoaned in short laments by keen growers of alpines. It was called Campanula rapunculoides, a menace of the first order with, they said, impossibly invasive white roots. For some good, now forgotten, reason I then became keen to grow as many forms as I could of the campanula’s near relation, another blue-mauve flowered family called Adenophora. In East Anglia I even found one labelled in a small nursery, located thanks to the RHS Plantfinder, the list of so many hundreds of British nurseries. The proprietor sold it in good faith and so I planted it in good soil between paving stones. Dear heaven, it has turned out to be the dreaded rapunculoides, imported by my own volition. I defy you to find a “green” answer to its hyper-invasive ways. It will have to be poisoned, although eight nurseries still offer it openly in the current Plantfinder. It joins a tall yellow-flowered Helianthus which is as invasive as a Jerusalem artichoke, rampant Inula hookeri (30 listed suppliers) given to me by the great Christopher Lloyd and the beguiling, suckering Elaeagnus Quicksilver, all utter menaces which I have imported or bought unwarily. Never accept an unknown quantity.

Other campanula acquisitions have been more happy. The family has recently been increased by careful selection and breeding, mainstays of every keen gardener’s life. Three newish ones are excellent, opening new possibilities for all of you with artistic eyes. Campanula Kent Belle needs staking. Campanula Sarastro needs cutting back. Campanula Samantha has nothing to do with the prime minister’s wife but goes on and on, nonetheless. I doubt if it has yet dawned on the Downing Street garden. Here is what you get from all three.

Adenophora polyantha

Kent Belle, on damp soil, can be up to 4ft high. It has hanging deep violet blue bells with a sheen on them, like a ball dress, or so its lady selector thought, thereby explaining her name for it. Mine stops at 3ft and needs a discreet pair of canes behind it to hold it all up. It is a lovely plant in flower, unknown about 20 years ago. Sarastro is more of a purple-blue, with a wax-like appearance to the bells but extremely good because it flowers twice at a height of about 2ft. By cutting back the stems at the end of this month you will encourage a second round of flower in September. Samantha is smaller, under a foot high, and her flowers are a shade of pale blue. She has a scent if you bend down to it but her supreme virtue is to flower almost continuously from spring till autumn. Perhaps she can be cross-bred into others in this family and pass on her relentless stamina.

Each of the three can be split up into many more plants after a year or two in the garden. They change the game in ways we have yet to exploit. While weeding among them in the half-light I have been reflecting how these small new observations and bits of breeding transform the supposedly staid world of flower gardeners. I really do not need some new “style”, telling me to grow plants only in brushed concrete or in competition with grass in a meadow. When outsiders ask, “what is happening that is new?” it usually means they are not keen on gardening. A perfectly good answer is the continuing proliferation of well-chosen new plants if you watch out for them.

Campanula persicifolia

While weeding my main campanulas, I had a different thought. The ultimate candidate for fashionable “sustainability” is a garden of nothing but groundelder. Just imagine. It grows “naturally”. It is green-leaved throughout the growing season. I am sure it ranks by now as “indigenous”. It attracts no disease and it needs no chemicals to help it. The variegated form is even rather pretty. If “sustainability” is to be the gospel of gardening, by what principle will its apostles rule out groundelder? I found myself asking this as I sadly ejected a good hunk of the tall milky blue Campanula lactiflora because groundelder had run through its main roots. It would be ineradicable if left. The uprooting exemplified a valuable truth. This fine campanula, up to 5ft high and a mass of flower in July, has thick fleshy roots which equip it for life on dry soil in dry summers. If I decide to go more natural in older age I must remember to split this essential plant and make it a keynote of the new informality.

Lastly, the bellflowers we all recognise. Campanula persicifolia seeds harmlessly everywhere and is the loveliest companion for the last of the shrub roses. This year the two are coinciding beautifully. If you want to introduce this classic plant, buy a packet of seeds right now, sow them in a well-watered box of light soil and reckon to have a good crop in about three weeks. Grow them on, transplant them to boxes with a bigger spacing between each of them and ideally pot them on individually after that stage. Next spring you will have dozens of your own bellflowers for minimal cost, waiting to go out and colonise the garden, even in half-shade. That really is gardening. Then, you can dead-head most of their stems beneath the rising moon, reflecting that the plants are yours and that you are doing them so much good in the half-light.

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