‘When a man knows he is to be hanged in a fortnight,’ said Dr Johnson, ‘it concentrates his mind wonderfully.’ We have longer than a fortnight, and the issue is not hanging. It is moving house. But it is wonderful how it concentrates our minds.

We have lived at Saling Hall for 42 years. The house and garden have that familiarity which is easy to identify, or perhaps confuse, with love. You notice the slightest change in the loved one’s features or demeanour and find, or try to find, an explanation. The return of honey fungus or a blocked drainpipe is easy to diagnose. But the whole person, the whole place, remains mysterious. Its dimensions are easy, its spirit is elusive. You cannot stand outside yourself.

So we are to move. Before Easter when the garden will be full of buds. Our first instinct is to list the plants and objects we simply must keep hold of by taking them with us. There’s a game for the long dark evenings ahead. Our second is to speculate about the garden: what will happen to it? How soon will our vision be overlaid with novelty, with neglect (unlikely in this case, I’m happy to say) or just by changing priorities?

We are incredibly lucky: our successors here are already friends, who know the house and asked if they might buy it. Our luck is even more incredible because this is the second time the same friendly arrangement has happened. When we sold our farm in the Bourbonnais eight years ago it was to the godson of a friend. Somehow continuity seems priceless. It was, of course, the rule in the centuries before estate agents existed. We may have no influence on what our successors do, but it is reassuring to think in terms of a baton being handed on.

Remember when we got our first Camcorders? It was in the late ’80s or early ’90s. It was thrilling to be able to film our surroundings so easily without fussing about camera settings. The way the new device adjusted to light conditions was uncanny: you could almost film a rabbit going down its hole.

The results have been standing, all but forgotten, on a bookshelf here for 20 years or so, hard to look at without resurrecting ancient technology. So have our video tapes in different formats, in many cases our only real record of what was happening in the garden at the time.

So we have had them converted to CDs (by a firm called Snappy Snaps) so that we can look at them on the television set or a computer. Even perhaps edit them – if I knew how.

How much better this garden looked 20 years ago. It was in its heyday then, 20 years after planting. Our original intentions were clear, unblurred by failures and over-exuberant successes. Compromise, I’m afraid, leaves indelible traces, and compromise dogs us as we settle into middle age.

But our most exciting rediscoveries are the films I made of our new property in France, lingering lovingly on every detail of abandoned farm buildings, manure heaps, overgrown ponds and rows of hideous telegraph poles. I was so absorbed, it seems, that I forgot to provide any commentary: the pans and zooms are all  performed in solemn silence, broken only by the cuckoo and the nightingale and the tinkling of streams – the perfect soundtrack.

The films record, spasmodically, nearly ten years of development. I even found my tongue along the way, and started to reveal, in a stuttering sotto voce, what plans I was hatching for ponds being dug and streams redirected, copses planted and alleys aligned. I could not have been given a more exciting present than my own past, my projects unfurling, succeeding or failing. Where is that old Camcorder? I must get it out and dust it off. No, I forget: almost any camera can film things today.

Charlotte's eye view of America in France

When we went back, in a fit of nostalgia, to our old farmhouse in the Bourbonnais last summer we were delighted to find it in better order than ever, the garden spruce and the house brimming with the family who bought it from us eight years ago. They gave us lunch at a long table in the shade of the plane trees we planted 20 years ago, a pleasure I didn’t think we’d ever have.

‘Is my (very) old Land Rover still going’, I asked, ‘may I take it for a spin?’ I wanted to do my old circuit of my plantations and ponds, to see if my new tracks and the alleys I made though the woods were still navigable. ‘If we can come too’ said our friends.

They were more than navigable, in fact in much better shape than when we left. As I drove they asked me about every twist and turn; why these trees here and those there (they are mainly oak and pine); how I discovered this spring or made that pond – and why that one had collapsed into a muddy puddle.

But best of all were the questions from the 18 year old daughter. She wanted to know the names of the trees and where they came from. She wants, she says, to be a landscape designer, wants to study in England – and tells me my work is her inspiration. Imagine what that does for the morale.

This week she emailed me some photos of the little valley where I planted American trees that colour cheerfully in autumn. There was deeper soil and more moisture there (in an area of generally gritty, unhelpful ground). I planted sugar and red maples, pin oak, scarlet oak and willow oak, some larches, Cryptomeria japonica, bushy vine maples and spindle. The fireworks are only just starting, but they are already converting one bright French girl into a future paysagiste. I am a lucky man.

When it gets dark at tea-time I look around my bookshelves in a different mood. It isn’t the latest book I want to read, but one that carries me along on the broad tide of thought that spans generations; indeed centuries.

Gardeners have always had the same preoccupations, and similar questions in mind. Their priorities change, and so does their rate of progress in answering questions. 170 years ago progress was in overdrive, as I learn on consulting one of my favourite winter evening resources: The Gardeners Magazine.

John Claudius Loudon conducted this magazine, the first of its kind, from 1826 until he died of editorial exhaustion in 1845. In 1842 Queen Victoria had been on the throne for five years. It was a time of exhilarating progress in many spheres. Reading Loudon’s review of the year 1842 is positively exciting. The German chemist von Liebig had just discovered the value of nitrogen to plants and revised the whole science of manure. ‘The higher the animal the better its manure’ was one of his sayings, with the conclusion that ‘night soil’ was thus the best manure of all – as the Chinese well knew. Liebig propagated the idea that roots need oxygen, too. He advocated mulching to keep them near the surface, and using a mixture of unsifted rough turfy soil and stones in pots to increase drainage. Plants that needed protection under glass became hardier this way, he found.

Joseph Paxton had just built his Chatsworth glasshouse with bigger panes of cheaper glass than those used before – starting a craze for greenhouses. ‘Strained wire’ was coming into use for fences that were ‘inconspicuous and  cheap.’ The ‘increased taste for the pine and fir tribe’ was bringing conifers into gardens. Ferns and ferneries were coming into fashion. Loudon had advocated, with remarkable success, the proper drainage and weather-proofing of workmen’s cottages. The queen did her first ceremonial tree-planting (at Taymouth Castle), signalling a new tree-consciousness. Loudon persuaded the authorities to label the trees in Kensington Gardens and St James’s Park; a momentous move for, among others, the nursery industry. And Chevreul’s new colour wheel was circulating among gardeners, revolutionizing their colour schemes for flower-beds.

The Gardeners Magazine was an extraordinary community effort. Loudon persuaded and provoked gardeners world-wide (there are notes from India, America and Australia) to communicate their experiences in a way that every good editor should, but very few have. How he would have loved the Internet.

It was when the Creator was making all His ingenious arrangements for His new earth that His eye fell on something that one of His beautiful mammals had dropped on the ground. ‘That doesn’t look very nice,’ He said to Himself. ‘Couldn’t I do something clever with that?’

Only the day before He had solved one problem that was worrying Him. The earth, or parts of it, looked rather monotonous month after month, all leafy, but a bit samey.

Then a new word had popped into His mind, as words do. ‘Deciduous,’ He pronounced it. ‘I’ll make half these plants deciduous. Then all these leaves can turn jolly colours and drop off, and we can have a lovely fresh start in spring.’ It meant, of course, a bare patch in between while the new lot of leaves and flowers were getting ready. Mightn’t people feel a bit depressed, with cold weather, not much light and everything bare?

This was when He noticed the mammal’s contribution. ‘There’s a challenge,’ He said. ‘Let’s see if I can turn that into something to cheer everybody up.’ So He made it sprout lots of whimsical little pink flowers and painted its leaves with pretty silvery lines. And ever since, when deciduous plants go bare, the cyclamen puts on its show and everybody smiles.

A future without ashes? More or less devastating depending on where you are. When the elms went in Essex (and the memory is still  raw) the young oaks and ashes in our copses and hedges were our hope for the future; the silver bat willows the quick answer, providing the missing dimension of height to the denuded fields – at least where there was a stream.

Forty years later the transformation is complete. Ashes and oaks provide the framework to views in all directions. Happily in the country round us oaks are in a majority of at least 2:1 and I know of few places in East Anglia with anything like a monoculture of ash.

Our own best ashes, in fact, are in North Wales. They line the rushing streams where they cut deep into the hills, growing among boulders and ferns. Curiously, in the high humidity of sheltered valleys and often daily rain their smooth trunks become bright orange, flecked here and there with green moss. I have never seen so bright a colour elsewhere; could it be a local phenomenon?

Meanwhile their seedlings come up like cress all around. Why do British nurseries import trees like this wholesale from the Low Countries? I put the question to a chairman of the Horticultural Trades Association at a Chelsea lunch a few years ago. ‘Because we’re inefficient’, he said, ‘and the Dutch government somehow subsidizes their nursery trade’. If this were true it would raise a lot of questions – about the workings of the Common Market, for example.

And what to plant in the place of ash? There is not a wide choice of natives that could take its place. In most soils the field maple (though never so big) would do well. Alder is fine in damp spots, especially in winter when it is festooned with catkin and fruit. But disease threatens our alders, too.

First choice should be the small-leaved lime, Tilia cordata, a too-rare native that fits perfectly into our lowland landscape, can grow to a fine height and can live for centuries. The scent of its flowers in late June is intoxicating. The place not to plant it is in car parks; it can drop honeydew. Seedlings are rare – which is presumably why it is not better distributed.

Perhaps our nurseries should start propagating it now before the Dutch get the idea.

I’ve seen enough hayfields. At this time of year there is hay in every garden, hay wherever you look, hay on my mind. What is all this about grass as a show plant for borders, for beds, for front gardens and back, parks, squares and courtyards?  Grass has its qualities, I agree. It soothes, it nods and sways in the wind, it looks great with the sun behind it (but what doesn’t?)

What’s wrong with it is that it’s in fashion. No self-aware garden can be without it. Every designer is using it. Every nursery has pots of it. And I think we can do better.

Grass is not like topiary – the other ‘in’ subject. Topiary never went out of fashion, but that doesn’t mean it can’t come back in. Grass (unless it’s properly mown) looks ephemeral, indecisive, blurs the edges, just looks too darned easy. It’s a cop-out. Choose among colours, shapes, heights, textures, time of year for flowering and fruiting, matching or contrasting. Adorn your garden with nature’s most elaborate and beautiful genitalia. Pick flowers.

Home from California to a near-drowning garden. There have been no cold nights to start leaves turning, and no sunshine to cook the colours. Red is simply not present in the palette, except in that guaranteed pillarbox, Acer p. ‘Osakazuki’ , and even he is reluctant. There is yellow here and there but little brilliance. And many trees have simply shed their leaves – certainly not for lack of water.

We had invited neighbours over on Saturday, even enticed them with a glass of wine, to see what is usually a pretty calorific display. On Friday, with more rain and a north wind forecast, I emailed them again, saying don’t bother, but we’ll try again in two weeks. By that time at least the Japanese maples en masse should have caught fire. But I gather from Tony Kirkham at Kew that their trees are baffled by this autumn, too. I should have learned that the best results arrive at the last moment.

So, dry indoors, we have been editing old transparencies, going back to our arrival at Saling in 1971. Even one of the big red removal van at the front door. The elms soared above everything then – but only for the first five years. The thought of an ash disease makes me shudder: where the elms died it was the ashes and oaks that gave us hope and slowly supplied the missing vertical element in our landscape. We thanked heavens for the speed and grace of the silvery cricket bat willow. We still do.

Looking at ancient transparencies makes me realize how easily we accepted some terrible photographs. Most of the illustrations in The Garden in the1970s, when I was in charge of the magazine, look dire today. I used to consider a transparency with a clear image, adequately lit, a success. The ones I am chucking out revive lots of sweet memories, but only just. Most are plain gloomy.

I thought in the 1970s, and I think now, that we underuse the admirable Norway maple in this country. If we are looking for a full-size, quite fast growing tree to back up our modest native choice (and we are), the Norway maple is an excellent candidate. It is not so tough and wind-resistant as its cousin the sycamore Not a candidate for the seaside. But it is infinitely more attractive, with its yellow flowers in spring and its reliable yellow autumn colour. Indeed it is one of the brightest things in the garden today.