Can you think of a sillier place for a garden than the middle of the Thames? Well, yes; perhaps the middle of the Channel. And that’s only horticultural speaking. Airports, Boris, by all means, but if you have a yen for putting things in mid-Thames, why on earth a garden? What need or question does this project answer – except the murmured ‘Will you?’ of a famous actress?

The Garden Bridge project could not have been proposed by a gardener. A long narrow strip of garden perpetually exposed to all the winds, with a limited depth of soil, and the need for constant irrigation, has little prospect of happy plants. Of tall and flourishing trees, I suggest, none.

Being planned as a popular spectacle the planting would have to be colourful – which inevitably means exotic. The computer-made prospectus shows something not unlike the Chelsea Flower Show crossed with a right of way: which wouldn’t work at Chelsea. But is it a right of way? Apparently not – which puts its status as a useful bridge in doubt.

What is its purpose? To add to the tourist attractions that make, for example, Bridge Street at Parliament Square a squalid jam of people and pushchairs and cameras. Picture the steps up to the Garden Bridge lined with hotdog and postcard stands. Picture the squads of Chinese tourists we must apparently encourage if London is to prosper. And shudder.

The bridge is proposed to join the Temple to the South Bank. The Temple is the only serene space on the embankment (ironically the site of the RHS Great Spring Show before the First World War). The South Bank is already a tourist circus. In a successful city, presumably, serene spaces are just unmarketed opportunities.

What is worst, though, is the impact of the bridge on London’s greatest view, the one Wordsworth celebrated: the great grey tideway itself. Nothing is more elemental and nothing more urban than the Thames passing between its embankments and foreshores and under the monumental bridges between Westminster and Tower Bridge, and the ceaseless water traffic using it. To interrupt it with a line of greenery would be like putting window boxes on St Paul’s.

Meanwhile the budget of Kew Gardens has been cut so deep that fifty botanists have been ‘let go’. If there are millions to spend on gardening the actress and the mayor must not be allowed to waste it.

I was going to try not to mention it, but the goings-on next door are hard to ignore – and getting harder. At the moment the drilling about three feet from my head threatens to upset my syntax. And no one can fail to notice the scaffolding to the top of our neighbour’s house and high above it, clad in white sheeting with the words London Basement repeated six times; one for each deck. ‘Is this the highest you’ve ever dug?’ someone asked.

Basements of course, are all the rage. A pocket calculator will tell you that with property at £x per square foot and the cost of digging and building at half x or less, the opportunity of adding a thousand square feet or so is worth considering. And there is no legal obligation to consider the neighbours. Decent people do, of course, but the law says the ground under your house is yours; by all means become a mole. A recent regulation says that, in this borough at least, you can only dig under half your garden (it used to be 85%). But a hole is a hole, and the diggers and the concrete mixers, the big white box on the pavement, the lorries, the noise and the dirt are a fact of life. So is the looming risk of cracks in the party wall or worse. What happens if power cuts become endemic is an unasked question. A corner candle shop? Our neighbours, though, have an immediate problem. Removing the plaster from their flank wall (it’s the last house in the terrace) revealed serious cracks. The whole wall, says the Council, must be demolished; effectively only a massive Virginia creeper is holding it together. That means the roof has to go – and the back wall, it seems, too. Its lusty wisteria, checked in its climbing only by the height of the chimneys, has already had the chop. We will be living next to a void, with only the stuccoed façade as a neighbour.

The scaffolding is just as imposing from the garden. You don’t see it from our windows, but looking back from the greenhouse end I try to persuade myself that in a moment of whimsy I commissioned a pagoda. Meanwhile the neighbours’ garden is like an unnaturally house-proud mining camp. On fine days the miners sit around, speaking a language not distant, to my ears, from Russian, outside their gemütlich little dacha. Why should they care that under their feet, under the flooring they installed, a terrible menace is advancing across the garden towards ours?

How do you extricate phyllostachys from the roots of a mature walnut? We may become experts when the miners move on.

It can get pretty tense when there’s a slot to plant in a tiny garden like this – or rather, when some bolshy radical, impatient for change, says there is. There’s immediately a lobby in defence of the plant to be, as it were, supplanted. “It looks fine, I like it where it is”. There are, though, no grounds for an appeal to variety: it’s a box bush. One of quite a number.

“I’ll put it in a good big pot”. (There are quite a number of these, too). “Don’t you think we need a bit of action there; a plant that performs – even flowers?” “Well, I like the green; it’s soothing”.

The real problem is that there’s no obvious candidate – or at least one that isn’t a thumping cliché around here. Does it matter that everyone else grows it? After all, the park is full of planes, and Tuscany of cypresses.

I see a cliché as a wasted opportunity. The pleasure of our little space is close-up observation of something that isn’t going on all around us. So unusual, even rare, is good. And something that will thrive in rooty competition in almost constant shade.

I’m thinking shrubby; something that will earn its space, with its back to the west-facing, plant-covered wall, with a jumble of herbaceous stuff in front. The neighbour’s walnut takes most of the afternoon sun. I look in the shrubs-for-shade lists. Of course most of them are evergreen. And no thank you, I don’t want Forsythia: or anything early – or anything yellow. In this garden roses belong on the walls (and indeed way above them). London is not rhodoland – though it is the epicentre of camellias. I have mulled over Japanese maples, but their spread would preclude planting close to them (and we have a beauty, a Saling seedling) in a pot. Viburnum? The best is V. burkwoodii, which we already have trained up a wall. Bodnantense? Our neighbours have a huge one (which we love). V. tinus stinks. V. opulus “Compactum” is possible: not thrilling, but pretty in autumn with turning leaves and shiny berries.

Callicarpa bodinieri is a possibility. Would it flower and produce its alarmingly- coloured berries in the shade? One to put on the short list. Would a deutzia perform? How about Dichroa febrifuga, a dark-blue-flowered hydrangeish thing we saw in New Zealand? It would be lovely to have, but it comes (if you can find it) with scary health warnngs. Holodiscus discolor: there’s an idea. Something that ornaments Douglas fir forests on Puget Sound doesn’t sound very urban, and certainly doesn’t have conventional petalled flowers. But its tall arching stems and its little oaky leaves (one of its past names was quercifolia) would look graceful, and its long buff tassel flowers, like a spirea, are exceptionally elegant, turn brown and ornament the winter too. To be considered. Cornus: now there’s a family….

To be resumed.

Perhaps not everyone knows that the grand iron gates in Piccadilly are the entrance not only to the Royal Academy (Sir J Reynolds in bronze, brush poised, makes this pretty clear) but also to the botanists’ Valhalla, the Linnean Society. Valhalla seems appropriate for an institution with a Swedish patron saint.

I was there this week for meetings of the International Dendrology Society in the august Council chamber. On the walls and the staircase hang portraits of every canonized botanist, The Old Lions and many plant collectors, from Linnaeus on – with a particularly colourful one of the late Professor Willy Stearn cheering up the Council chamber. From the windows on one side you look down on the Royal Academy, from the other you survey Whitehall down to Westminster Abbey. It could go to to a mere gardener’s head.

The IDS holds its annual Winter Lecture here. This year it was Tony Kirkham’s turn. His subject: 250 years of Kew Gardens and gardeners, from Princess Augusta and poor Fred, Prince of Wales, down the long avenue of celebrated names: Bute, Banks. Hookers sr and jr, Thistleton-Dyer (Tony’s favourite, though a martinet. He wore a dashing uniform), Dallimore, WJ Bean….and Kirkham. Tony has been capo of the arboretum since 2002, totally immersed and most eloquent about his charges.The progress of Kew from a minor royal garden with a mere 5 acres of arboretum to its 300 acre splendour today makes a good story – especially since half a dozen of the original trees planted in the 1760s are still there, feted as ‘the Old Lions’ and propped and botoxed-up as necessary.

The most wonky, now lying on its side, is the original Pagoda Tree, recently relabelled Styphnolobium japonicum, though Sophora japonica to you and me. What an indignity, handing it a 5-syllable genus at its time of life. What tin ears botanists sometimes have – or in this case the Viennese publication that got in first with a name in 1830. Surely the label should at least acknowledge the name it bore for most of its existence here. There could be an acronym, FKA (formerly known as) or even TYAM (to you and me). The other Old Lions, considerably less mangy than the first, are the oriental plane, the original ginkgo, the huge Zelkova from the Caucasus and the Robinia or False Acacia, named for Jean Robin, director of the Jardin des Plantes in Paris (who presumably got in first).

Princess Augusta might be nonplussed to find some of her old trees growing where they do. Shifting them around has long been a practice at Kew. When the Duke of Argyll, another acquisitive dendrologist, died, his nephew Lord Bute took a gigantic horse-drawn wagon and helped himself (or rather Kew) to the best trees on Argyll’s Richmond estate – including the robinia.

Galanthus mobilia

To the Chelsea Physic Garden on the first of its two Snowdrop Weekends. Nippy at 4’C with a north wind. A marvellous coup de théatre on the way in: snowdrops as mobiles hanging from trees in little balls of moss; snowdrops as a rug round the cold feet of Sir John Soane in marble, and snowdrops in drifts along a newly-created path winding through the trees down by the Embankment.

The CPG keeps getting better – and even apparently bigger, as more little gardens and gardens-within-gardens and different horticultural incidents enliven its space. It’s hard to believe that so much can happen within its four acres, including a considerable arboretum of seriously senior trees. Somehow there always seems to be another unexplored or undeveloped patch to be transformed.

Nothing could be more inspirational for an urban gardener – or any gardener with very limited space. Here is the evidence that you can pack it all in, divide your space again and again, shift the focus from one style or environment to another.

Rockery, economic plantery, perfumery, pond, bog garden, woodland garden, order beds, fernery, Antipodean collection… they merge or contrast (more of the former in winter; the latter in summer) to make a magical garden walk, absorbing hours – even on a nippy January afternoon, when galanthophiles have their moment of glory.

I love snowdrops – but that doesn’t make me a galanthophile. On the long table in the sales tent (same temperature as the garden, minus the wind-chill) patient volunteers with frozen feet were guiding us through the differences between the precious named cultivars. Most people ask about the big ones, largely selections of Galanthus elwesii with taller or shorter flower stalks, bluer or greener or broader leaves, and heaven-knows-what variations of exquisite detail in their flowers – at £25 a plant. I’m afraid I asked the obvious question: what about the undifferentiated species? ‘Yes, we had quite a few, but a French woman took the lot this morning’. They have their heads screwed on, the French.

For all the winter chill, the most eye-catching plant in the garden was, of all things, a rose; a handsome mound, seven feet high and wide, of fresh green with reddish emerging shoots and tender leaves. It carried forty or fifty pale scarlet flowers looking none (or only slightly) the worse for the frost. Rosa mutabilis? I wondered. Then I thought of ours, hunkered down and almost bare. Surely a relation? ‘Rosa odorata’, said a cold-footed volunteer. ‘We used to say Rosa chinensis Bengal Crimson, but we’re not allowed to any more.’

It’s what I do on dark January afternoons; retreat a century and half to the world of frock-coats and crinolines, the world of JC Loudon, John Lindley, Joseph Paxton and William Jackson Hooker, the years when gardening was just finding its scientific feet.

My time-machine is The Gardener’s Magazine. I am deep in the issues of 175 years ago. John Lindley, secretary of the Horticultural Society, has just published his Theory of Horticulture, described by its reviewer as ‘as useful and indispensable to the gardener as the compass is to the mariner’. Lindley began by explaining in plain terms how plants work, in ‘a short guide to the horticultural application of vegetable physiology’. Such a thing, it seems, did not exist; gardening was learnt only by tradition and experience. “If I had met with such a book as this twenty years ago I would not have so many grey hairs in my head now”.

Paxton had just built the Great Stove at Chatsworth, the prototype for the Crystal Palace. Loudon enthuses about what the new Penny Post would contribute to gardening, making the distribution of seeds and cuttings possible as it had never been before. The nobility, and even commonplace millionaires, were investing in more and more ambitious gardens, nurserymen were flourishing and plant hunters ranging further than ever. And yet, in January 1840, the government announced it was closing down the royal gardens at Kew. All the plants were offered to the Horticultural Society – at a price. The Society declined; they were offered gratis to anyone who would take them away. And the greenhouses were to be demolished.

Strange, I think, that Paxton’s boss, the 6th Duke of Devonshire, with his house at Chiswick, just between Kew and the Horticultural Society’s Chiswick garden, didn’t put two and two together. The job of saving Kew was achieved largely by John Lindley and his friends, lobbying the Prime Minister, Lord Melbourne. His friend William Jackson Hooker became the first director of the new establishment.

I close my magazine and pick up the newspaper. What do I read? Kew’s budget has been cut again. The world’s most important botanical garden is to be cut down to size. They have already laid off fifty scientists. They may have to be closed to the public out of season. And London is to have a new public garden – on a windswept bridge, of all places, crossing the Thames from the Temple to the South Bank. At a cost of £175 million. Putting two and two together still seems to be too difficult.

How much more room for progress is there in photographing gardens? Books like The English Country House Garden, out at Christmas, by George Plumptre with photographs by Marcus Harpur, seem to have perfected the dream scenario of consummate skill and taste in design and execution – first in gardening, then in photography. They create a never-never land of perfect flowers, perfect viewpoints on perfect designs in perfect weather. Rough winds come nowhere near.

Harpur is the inheritor of a strong tradition, son of Jerry Harpur, whose books encompass for more than the usual round of English gardens. He may have been the first to show us great gardens from all over the world. I once bumped into him in a lakeside garden high in the Andes.

His unglamorous roots were in Essex, following in turn in the steps of Harry Smith, whose garden picture library was the first resource of magazine editors in the 1960s and ’70s. In due course the archive was taken over by Anthony Huxley and Dick Robinson, the photographer who gave his own garden at Hyde Hall to the RHS.

Hyde Hall was a horse whose mouth needed careful scrutiny. The Robinsons’ garden was a triumph of hope over experience, an isolated hillock in the driest part of England, windswept, with no proper access, its views featureless except for pylons. It is unrecognisable today, after decades of RHS investment, but it was a bold move to take a stake in a part of England as unlike leafy Surrey as could be. Essex was not without its garden history: Ellen Wilmott of Warley Place, Beth Chatto at Elmstead Market, Audley End, the Gibberd Garden, Rivers nursery, Pemberton’s roses…. and dreams – the role of photography.

Where does garden photography go next? Technical perfection is in the bag. We would laugh, today, at the grimy images of only thirty years ago. Beyond the purely descriptive, perhaps? The Garden Museum is putting on a show of pictures by Rachel Warne called Faded Glory. proving the visual strength of neglected or abandoned gardens. (My favourite of all the photographs in my own book, The Principles of Gardening, was the opening page; Kenneth Scowen’s shot of an abandoned Edwardian Garden fountain in winter, overgrown (but just to the right degree) with long grass and thistles and old man’s beard.)

But the museum director, Christopher Woodward, has form when it comes to ruins. His own book, In Ruins (Chatto 2001), is a masterly evocation of what they say to us. Far more, perhaps, than straight edges and weedless borders. ‘When we contemplate ruins’, says Woodward, ‘we contemplate our own future’

I was surprised by my own excitement in the garden this morning. I’ve discovered over the years that it isn’t only plants that notice the days being a couple of minutes longer. It stirs human blood, too. Especially on a day of brilliant blue sky.

But the excitement came from a sudden rush of memory of all the things I’ve planted in the last year and shall enjoy in the coming one. Bulbs, of course, but mostly plants that have just ticked over as they are taking root and will really make their entrance in the months to come.

The previous year’s planting (our first) was quick to make a difference. My screening trellis on the end wall is a tangle of solanum, clematis, rose, jasmine and eccremocarpus. There is a big spring job waiting for me here, mostly in taming the marvellous white solanum. I have even warned people myself that this plant is a colonizer. 18 months in the ground here, in an almost undiggable corner under the sycamore, has given it a wingspan of something like 30 feet in our garden and our neighbour’s. Just now I noticed that a stray tentacle is still flowering (it’s freezing hard) in a potted standard of another solanaceous thing, Ipomea (or Acnistus) australe. Few shrubs have the honour of a pot here, but the blue bells of Ipomea have seduced me. (There is a shrub 12 feet across in the Chelsea Physick Garden).

The plants that haven’t yet really performed are a couple of climbing roses and the viticella clematises I look to to colour our trellises late in summer. It always seems a pity to do as the books say and chop them down just as they get a good purchase among the other climbers. One of the clematis (the potentially sumptuous C alba luxurians) and two roses have everything to prove. I discovered them totally suppressed, in a sort of coma, overwhelmed with ivy and hydrangeas.

One rose, fed and watered for a year now, still hasn’t flowered (though its reddish leaves look familiar). Of course the longer it takes the keener I am to know what it is and decide which way to point my thumb. Another one only took a few months to declare itself – and Iceberg can never be unwelcome.

There is anticipation all around: small brainwaves that haven’t yet crested. I planted a Daily Telegraph collection of three pulmonarias; they should be quick to show their colours (white and blue). Last year’s discovery, Salvia vitifolia, is snug under a compost duvet (for as long as I can keep the local cats away). A fox visits our unguarded front garden. If one scrambles over the trellis into the back one I shall not be happy. Nor can I understand why we tolerate these disgusting animals in cities at all.

I hung silver balls in our big front magnolia for Christmas. I see no reason to take them down before the velvet buds open and surround them with purple petals.