It's first flower opened in December. Can anyone name this camellia?

Squelching around Holland Park, as I do most afternoons, there is no mistaking the fact that spring has its foot in the door. Daffodils are opening their buds. The kerria in the Japanese garden is out; borage adds blue to the muddy tangle in a ditch. Porcelain-white Chaenomeles ‘Nivalis’ has been in flower for three weeks and what I took to be snowdrops in a lawn turned out as I got nearer to be daisies.

There has not, to my knowledge, been a single frost in London yet this winter. That ‘yet’ is important. The floods that are tormenting so much of the country amount to little more than puddles here, but I can’t remember any year when cold weather hasn’t arrived soon or later. I fear it may come in March, and remember with a shiver the weeks of East winds that last year made our departure from Saling Hall feel like a retreat from Moscow.

Are we getting a false impression of London life? I went out and picked a ripe lemon on the verandah last night from a tree happily flowering away in the rain. (Odd that rain doesn’t seem to inhibit the self-pollination of its endless flowers). The hawthorn on the roof outside my study is opening its buds three months ahead of schedule. The streets of Kensington are gay with camellias. I write this down so that I will believe it happened when things return to normal.

I can’t say I’m a connoisseur of garden centres; their combination of hoes and postcards, lasagne and water features, barbecues and whatever is in flower today may be a commercial necessity, but it somehow scrubs the part of any mind where plants and plans can usefully combine. I find myself filling the boot with things I’ve never wanted at ten percent off.

We made a detour, though, on our way home from Dolgellau, to visit Ashwood Nursery, near Stourbridge in a part of the country I don’t know at all. I had chanced on their website and been seduced by their choice of hellebores, daphnes, auriculas, hepaticas…the sort of things a gardener thinks of in winter. Especially a gardener with a tiny north-facing garden and a new greenhouse.

We were not disappointed. There was none of the usual corporate formula. It was clear straight away that this a nursery in the true sense of the word. Yes, the entrance/exit hall was full of china figurines (but even Kew trades in knick-knacks these days). Once past it, though, and the queue for the savoury-smelling café, the winter garden scene was perfect: intimate, enticing, jolly, with good plants and original ideas wherever you looked. The need for a gnome-land was handled with great applomb: you are greeted by a meadow of little model sheep. Then paths wind off through beds that look long-established and promising for all seasons, with enough January colour to spur you on; leading to glass houses on flower-show form, with the possibilities of the month excellently displayed and clearly explained.

No corporation, I thought, would have such taste or such high standards. Sadly we were there two weeks too early for the owner’s winter open garden day, but the photographs showed us what we were missing: a full-on demonstration of the possible, more personal and less stereotyped than any our public institutions give us. We shall be going back.

I. reticulata has passed though many hands, with many selections; this is apparently 'Pixie'.

Iris reticulata flowers two weeks after I. danfordiae – given identical conditions in the greenhouse. It has quite a different character though: a lady in party finery compared with a cheerful country girl. In the house her scent is quite different, too: more elusive, less nocturnal, delicate and piercing like a violet’s.

It has rained every day so far this year in North Wales – a state of affairs more unusual than you might think. The waterfalls are in splendid spate; just now we saw a group of daredevils canoeing down a fearsome sheer drop, free-falling through the spray. Our little river is in that sinister mood when it runs swift and silent, no ripples breaking its swirling surface. And the ground is saturated. I made the mistake of stepping off a hard track to skirt a fallen tree and went in to the top of one welly. Luckily not over the top, or I would have had to abandon it and limp back barefoot, the light quickly fading, half a mile downhill to the car – not a prospect to relish.

Worse, I was effectively lost. We have just clear-felled the spruce and larch on a wide stretch of hillside, and with the trees has gone all my sense of place. I was negotiating what had been a favourite bit of track, where tall trunks framed the first silver glimpses of the sea. Ferns were thick along the path, giving way to deep green moss and gleaming threads of water under the dark rows of trees. The track turned left here by a flat grey rock to skirt the steepest slope. There was no rock, and no track; just stumps and ruts and snaggy branches higgledy- piggledy everywhere. Getting back down in the dusk was tricky.

Forestry is a messy business; for long years calm, verdant, woken only by the flitting of birds; then suddenly the Somme. The place you knew and loved has ceased to exist. At least I am responsible, or at least obediently following the cycle of planting and harvesting. Foresters are to blame for the biggest changes anyone can perpetrate on the landscape, eliminating beautiful familiar places at a stroke.

So what is a “place”? How is it different from a map reference? A place has intelligence; it depends on understanding – of its purpose, its history, of the forces that flow through it. A landscape or garden designer’s job, or one of them, is to show you where to cast your eyes, and where to put your feet. There are forces at play in a design: sight-lines and pathways and the interplay between them. They are different in different seasons; winter transparency and summer solidity; the sun lower or higher in the sky; pale shadows and black obliterating ones. Colours, of course, and textures, eye-catchers and passages of restful green or grey.

All these contribute to a sense of place. They give you confidence, explain, perhaps subconsciously, where you are and why, what the gardener wants you to observe and enjoy, where you should go next to be excited or to be soothed into a reverie.

A resourceful gardener controls your mood; invites you to share his own, then changes it. It is the reason for the overwhelming success of garden rooms, of Hidcote and Sissinghurst and their many imitators. Great gardeners do it by suggestion, by modulating scale and colour, enclosing you or letting your eyes roam free, splashing water about or letting it reflect the sky: there are a thousand ways.

The forest will grow again – but it will be a different place.

There’s a limit to what the council will let you do to your trees in a leafy borough like this one. It has absolute power over the woody leafage. Not the power to plant a tree in your garden, of course, but the power to stop you disposing of it as you see fit. I am stuck, then, with a disproportionate amount of sycamore. I have reservations? A lack of proper respect? My problem: I bought the tree with the house.

In this privileged area, though, even the tree surgeons are a cut above the norms. I googled “Tree surgeons, Kensington” and stopped at the second name. Not a name to forget easily: Fergus Kinmonth – and one I recognised as a member of the International Dendrology Society and a visitor to our Essex garden. How many dendrologists climb trees with chainsaws? Probably not enough.

Fergus came round and we talked about the two trees that last summer kept the sun from touching our garden, the sycamore and the neighbour’s walnut. I know they get more than their share of publicity in this diary. But then they take more than their share of a diarist’s light.

Tooth-sucking from both of us. “They’ll let you take off the same as last time”, said Fergus. “That’s just the tips,” said I. “Precisely. This is a conservation area.” “So what is it they’re conserving?” “People don’t like it when the greenery they see from their windows is removed.”

I’m not keen, either, I admit. But here we have the politician’s dilemma. “If we want things to stay as they are, things will have to change” is not a message that public servants want to hear. So no radical tree surgery; just a snip here and there while the problem grows. Fergus and his team came and snipped – very handsomely and tidily, I must say. Not a twig is left: just a massive black tree-skeleton in the sky, ready to do the same again, plus a little bit – to need painful surgery again in a year or two.

Woke in the night with the scent of a pot of Iris danfordiae filling the bedroom. I have never grown this tiny turk before and was unprepared for its perfume. What insects are such flowers of the winter trying to attract? There are not many, and their scents, it seems to me, have something in common: a trace of honey and a musky facet which can become a little too strong at close quarters. Winter Heliotrope and Viburnum Bodnantense are both better at a little distance. There are wines that do this to me; Muller Thurgau, for instance.

When flowers use their energy to broadcast scent at night can it be moths they are after? Certainly they look eager for visitors; the little yellow irises stand bolt upright like nestlings with their beaks stretched open, beseeching food.

What is a dilettante? Someone to be admired, scorned or pitied? Would you admit to, or maybe claim, the title?

We had a lively debate about it the other night, one friend taking the fashionable view that it means uncommitted, non-serious, even amateur (and is therefore to be condemned). My view is pretty much the opposite: that it infers commitment of another sort, passionate interest rather than professional duty.

It depends on the context, of course: in medical matters we hope for certainty and rely on the apparatus of peer-reviewing. An amateur surgeon would not find many customers. In a different field, (planning matters concerning historic buildings are on my mind at present) the common sense and taste that an experienced dilettante can bring can be far more valuable than the callow judgements of a professional planner.

It is not uncommon for the long-brewed plans of an owner and his architect, arrived at after years of study of a site, its surroundings, its history and natural conditions, to be rejected – or certainly (almost inevitably) modified – by an individual who has no background knowledge of the matter. “I would prefer the door to be here”, or the window to be a casement, or a wall to be lower or higher, is a common, and completely outrageous, statement.

Outrageous because this individual’s opinion automatically acquires the authority of law. I don’t recommend questioning the qualifications, the judgement or even the bona fides of a planning officer. Seduction is more likely to produce the required result.

So yes, I am happy to call myself a dilettante – a word that means simply one who delights. A set of young aristocrats who made the Grand Tour in the mid 18th century (and were probably all at Eton together) met as a club under the name of the Dilettantes. Their inaugural meeting was painted by one of their members, Sir Joshua Reynolds. There are clubs and groups with similar leanings today, but who claims the delightful name?

And there’s another calling that has lost its meaning nowadays: that of the flâneur. A flâneur is one who strolls without intent – except to observe the world. Cornelia Otis Skinner, the author Our Hearts were Young and Gay, defined a flâneur as a ‘deliberately aimless pedestrian, without obligations or sense of urgency, who being French and therefore frugal, wastes nothing, including his time, which he spends with the leisurely discrimination of a gourmet..’ The critic Charles Sainte Beuve called flânerie ‘the very opposite of doing nothing” ; Baudelaire called him ‘the botanist of the sidewalk’.

Need flânerie be limited to sidewalks, though – let alone to the French? How else to describe what I do in someone else’s garden?

To Exbury the morning after the pre-Christmas storm. Remarkably little damage: almost none to the high oaks that provide the principle cover – or any of the deciduous trees. Cedars with their heavy rigid branches and Scots pines with their sinuous ones are always the main casualties. But below them, washed and polished by the rain, the rhododendrons and camellias and all the other evergreens gleamed in the sun with a thrilling look of promise.

It must surely be an illusion that immediately after the shortest day plants take on an attitude, or at least an appearance, of expectation and hope. I know primroses do: their leaves prick up with just one extra minute of daylight. The buds of rhododendrons seem especially alert this morning. Excited and exciting, in fact.

It is sad to contrast this thriving Rothschild garden with the family’s former estate in the western suburbs of London at Gunnersbury. Once Gunnersbury was almost as big and almost as horticulturally exceptional as Exbury is today. Its place in history reflected the

Rothschild fortune: Disraeli was an habitué; it is where Britain bought the Suez Canal. It is still in existence, but the only reminder is the anonymous green backdrop to a row of post-modern office blocks along the Great West Road flyover where it crosses the NorthCircular Road. Gunnersbury was one of the group of great houses that graced the approach to London from the west, or down the Thames: Chiswick, Kew, Syon, Osterley, Marble Hill, Strawberry Hill, Ham and further upstream Hampton Court.

The creator of Exbury, Lionel de Rothschild, was brought up at Gunnersbury, but when his father Leopold died his mother sold the estate to the local councils of Acton and Ealing (at a fraction of its potential value) to remain as pleasure grounds in perpetuity.

Sadly the ratepayers have seen it more as a burden than an asset. Some said that the other historic parks were plenty; no need for another. The grounds at Gunnersbury are merely maintained, the houses (there are two) in disrepair, the remaining great trees rotting and tottering. Today it has more archaeological than horticultural allure.

But there is hope. The two boroughs (now Ealing and Hounslow) have a plan for restoration and future use of the house (now a modest museum) and the grounds, are consulting the public and have appealed for Lottery grants of £17 million. It will be too late, alas, for the garden to recover its old importance. But I shall go in the spring to see the buds begin to swell.