Across the road from the library was a magnificent example of Sixties municipal planting: a memorial garden with a round bed laid out in an intricate patriotic mosaic of blue lobelia, red salvia and white alyssum, flanked with low brick planters in which French marigolds stood in orderly ranks, filling the warm spring air with their distinctive animal reek. This morning, instead of moving along at his habitual brisk march, my grandfather seemed to be hovering over the French marigolds — an unwise place to hang about, I could have told him, since they were a haunt of fierce fat bees. Between the clustering orange marigold heads and their sharp-cut leaves was a glimpse of something striped blue and white. I reached out and picked up a little round box. Inside was a wad of cotton wool, and underneath that, a little grey china cat. “For you,” said my grandfather.

I think that present gave me the most pleasure of anything I’ve ever received — the unexpected thrill of the blue and white box sheltering among the marigolds. And it has left me with a lingering fondness not just for small blue boxes with treasures inside but also for urban planting. Those familiar objects of sophisticated urban contempt — the salvia, dahlia, lobelia and begonia, the paintbox primary colours of primulas and Busy Lizzies, the foxy pong and retina-shrivelling hues of French marigolds and pelargoniums — I love them all.

This, I suspect, is because although I have lived in London for more than 30 years, my heart remains stubbornly provincial — and public planting is something at which the provinces excel. It is hard to travel through a town or village in Britain without feeling a sense of intense floral competition, both public, in the form of hanging baskets and planters, and private, in the brightly coloured idiosyncracy of people’s front gardens. Not so in our great cities, where people pave over their front gardens to park their ugly cars, and the streets of even quite prosperous boroughs are pocked with sad patches of bare earth, where broken-down saplings struggle amid a dismal mulch of dog-ends, crumpled drinks cans and KFC wrappers.

Every time I see one of these pathetic anti-oases (not to mention the dreary apologies for planting that characterise too many of London’s parks) I find my fingers itching for a trowel and a couple of trays of B&Q’s best striped petunias. But a chap called Richard Reynolds has done better than that. He is a 28-year-old advertising executive, and instead of tutting about the capital’s wasted spaces he has taken to planting them.

At dead of night, when no one is abroad but graffiti artists and urban foxes, Reynolds and his volunteers go out guerrilla gardening: double-digging, manuring, and popping in shrubs, bedding plants, herbs and even vegetables on barren patches of land. The roundabout at Elephant and Castle has benefited from his attentions, as have sites at St George’s Circus, Camberwell Green, Tower Bridge Road and assorted other bits of urban wasteland.

Guerrilla gardening, it turns out, is not a new phenomenon. It goes on in New York and Toronto, and (I learn from the internet, where if you Google “guerrilla gardening” you find out all sorts of interesting things) 150 years ago in northern Utah the canalsides were surreptitiously planted with apple trees and asparagus patches by the workmen toiling there. In fact, there is something so quietly and deliciously subversive about the notion of reclaiming neglected land by the simple action of planting a seed that, if you don’t mind, I’m going to stop writing this minute and nip next door to plant winter pansies and lavender all over the barren patch of urban wasteland next to my house, owned but unloved by London Electricity.

Bingo brings hopes of Violet in spring

There was horticultural excitement of a different kind in our street this week. On Wednesday morning at first light the road filled with people in Puffa jackets and unnecessary dark glasses. We were curtain-twitching madly, wondering what this large crowd of people was doing outside Violet-next-door’s, when at 7.30 there came a pounding at my door — an hour that even I, with my early-rising habits, regard as a bit advanced to be receiving callers. Would I kindly move my car, demanded an assertive young man, as it was getting in the way of the telly advert he was making for the National Bingo Game Association.

Coo! The excitement. Violet-next-door’s front garden is going to be a star of the small screen. Before she took to her bed in the autumn, Violet was particularly keen on bingo and, while suppressing a pang of envy that my own tasteful plantings of hawthorn and Lonicera fragrantissima never attract the crowds of admiring onlookers and telly crews that Violet’s gnomes and swags of imitation wistaria command, I feel a small shoot of hope unfurling. At Christmas Violet had resolutely turned her face to the wall and was discussing coffin handles with the animation that she used to reserve for earrings. But this advert won’t be shown until April. Which means, I reckon, that she’ll have to hang on until then. By which time spring will be on its way and the world beyond her bedroom wall much too full of promise for her to give up on it.

Fine whine

I read with interest yesterday’s Times report about the Sonic Teenager Deterrent devised by an ingenious businessman, Howard Stapleton, whose company sells the devices at £622 a go. Apparently they emit a shrill whining sound that sends teenagers fleeing. Fancy that. Mind you, I think I can save myself the £622, for our house already harbours such a device. As well as emitting a shrill, teenager-torturing whine, it supervises piano practice, irons rugby kit and does Latin declensions. Yes, it is I, the Maternal Teenager Deterrent, scourge of teenagers throughout SE10 and beyond . . .

Times Recommends

• Strip away the figleaf and reveal naysayers
• Dave’n’George: there may be trouble ahead
• I do not accept that £64,000 a year for politicians is peanuts