Charles Quest-Ritson offers his advice on taming this exquisitely flowered fruit.

I’ve never planted blackberries in my garden – at least, not until four years ago. I’m a country boy and I don’t see the point of cultivating a plant that’s widely available in the wild.

Over the years, one gets to know the good stretches of blackberries in fields and hedgerows – the ones with large fruits or superior flavour and the ones whose crop comes early in the season.

A friend of ours, a retired admiral, grows cultivated blackberries in his kitchen garden, duly manured, watered and trained along wires for easy picking, but he misses out on the fun of picking wild blackberries for free.

‘In short, the plant is hell-bent on world domination’

That’s the reason I can’t really explain why I planted a cultivated blackberry in the spring of 2014. I was thinking about soft fruit for our new garden and went to a garden centre to look at raspberries and currants, but the blackberry was in a pot and going for half price, so I thought it might be worth trying. It’s called Rubus Loch Ness, and I discovered later that it’s one of the few that carry an Award of Garden Merit from the RHS.

Over that first summer, it lingered, but, eventually, it put out some new growths that duly bore fruit in 2015. The berries were rather sour, but the RHS says that Loch Ness is one of the blackberries whose fruit colour up and look as if they’re ripe before they really are. The following year, I left them for longer before picking them and found that they did indeed have a good flavour, when both fresh and cooked.

Fast forward to 2018. Loch Ness expands by suckers, unlike ‘wild’ blackberries whose long wands arch over and root wherever they touch the ground. With Loch Ness, new growths shoot out of the ground all around the plant, up to a yard away from the previous year’s stems. They’re quite stout, so they don’t really arch over enough to reach the ground, even at the end of the year.

My squinny potful is now an enormous clump, heaving with promise. I reckon I shall get some 45lb of fruit off it before the end of September (my grandmother used to say you should never pick blackberries after Michaelmas, when the Devil enters them. Theology wasn’t her strongest suit).

Blackberries are borne on fruiting spurs that emerge from the axils all along their canes. Bumblebees like the flowers, but that’s not what they’re grown for, unlike those strictly ornamental Rubus, such as Tridel and Olympic Double, whose flowers are very pretty.

However, I have no hesitation in saying that Loch Ness is a spectacular sight when it flowers in May. The flowers aren’t especially large, but they are gleaming white and borne in huge clusters all along those near-thornless stems. They far outshine the deutzias and spiraeas that are everyone else’s bog-standard flowering shrubs for late spring.

For two or three weeks, the clouds of enthusiastic insects that Loch Ness attracts make it by far the noisiest plant in my garden.

Loch Ness Blackberry

It’s a pity the RHS doesn’t give its Award of Garden Merit to the flowers of plants that are principally grown for their fruit. In fact, the only one I can think of is a cooking apple called Arthur Turner, which got its award in 1945. (Actually, I think Annie Elizabeth, Ashmead’s Kernel and Keswick Codling have prettier flowers.)

I do think the society should make an exception for Loch Ness. It’s the very incarnation of health, vigour and beauty.

What’s more, it makes a cheerful, ever-expanding clump. Mine is now at least 15ft across and up to 7ft in height. Its growth is what mathematicians call ‘exponential’ or an example of ‘geometric progression’. Anyway, the suckers (next year’s fruiting canes) are now rather a nuisance.

They’ve invaded our autumn-fruiting raspberries and have entirely surrounded two young apple trees. In short, the plant is hell-bent on world domination. I calculate that, in another three years’ time, the clump will extend to more than 1,000 stems; in 10 years’ time to 100,000, enough to give one to every reader of Country Life who cares to call – but don’t wait, buy it yourself.

It’s wonderful to have something that grows so well, even if this particular Loch Ness is a bit of a monster.

Charles Quest-Ritson wrote the RHS Encyclopedia of Roses