I’m always baffled by dew and its effect on plants. It comes, of course, on clear and relatively cold nights, recently almost every night – which is odd because, though the sky has been a sea of stars, the temperature has not dropped as you would expect.

There is nothing mysterious about the process: the ground surface radiates its stored heat into the atmosphere, making it colder than the moisture-laden air, which condenses in drops – especially on grass. The quantities are not large, the equivalent of perhaps half a millimetre of rain at most. In drought conditions, though, when plants are under serious stress, it makes a difference.

The difference appears greatest where sunshine doesn’t evaporate it next day. There are patches of shade in this garden now where the grass has started to grow quite strongly, lush and damp all day. Paradoxically these are places that remain covered from the clear sky at night, where the dew falls must be less. Evaporation therefore seems more important in the equation than precipitation.

On the North Kent Downs where I was brought up dewponds were common. They consisted of shallow hollows perhaps 20 feet across and four or five deep, lined with flints, handsomely built and apparently ancient. They seemed to hold more fallen leaves than water. Apparently they were lined first with clay, then with a thick layer of straw, then with chalk, crushed fine and rolled to a smooth surface, before the flints were applied to protect it. The principle was to insulate the pond from the ground beneath and its radiation of heat; to make it a cool dish to attract condensation on clear nights. But a shower of rain, I’m sure, was even more welcome.

‘When they’ve finished the duckpond, can they have the moat?’ said the voice on the telephone at midnight. I recognized the voice: a neighbouring farmer’s. ‘Haven’t you heard?’ (the standard Essex formula for breaking news) ‘the coachhouse is on fire.’ The coachhouse is 400 yards away at the other end of the village. By this time I had opened a curtain to look towards the duckpond. It was invisible for flashing blue lights. We pulled on clothes and dashed out. There were three fire engines drawn up by the water, their engines throbbing, and a tangle of fat hoses leading out of the gates and down the street. The sky at the far end was brilliant orange and full of sparks.

When we reached the coach house the roof had fallen in and waves of pale flame were attacking the gables. Five more fire engines were throwing water at it. A man on a tall ladder held the hose from the village mains supply, issuing an ineffectual dribble. The duckpond was providing full jets from the other hoses.

An hour later the flames were under control and we went back to see fish floundering, as we expected, on the bottom of an empty pond. The level was down perhaps two feet, but there was a little way to go. The moat, happily, had not been needed at all.

Why am I recalling this now? (It happened in April). Because now, after a dry summer, the duckpond is lower than we have seen it in 40 years. You can walk to the island. When you empty a long-standing reservoir (and this has been here for centuries) can you be sure it will ever fill up again?

What is the absolute minimum that can constitute a totally satisfying garden? I found an answer last week in that paradisiacal part of France they call La Provence Verte, a region of pines and vines at an altitude that gives cold nights summer-long, very different from the sun-baked grey-brown garrigues of the country round.

We were staying with friends in one of those tall, almost urban-looking chateaux of the early nineteenth century, classical, well-proportioned, unornamented and a touch severe. The walls are a pale ochre, the shutters blue-grey. The garden is on two levels; that of the house and, linked to it by two stone staircases curving symmetrically round an oval bassin, a lower terrace, a simple lawn. Both terraces are surrounded by stone balustrades.

The upper terrace, the space in front of the house, is a plain unbroken expanse of that almost dust-fine gravel we don’t seem to know in England – but then we don’t play boules. It is shaded by four towering plane trees and one lime. The lawn below has four more planes, contemporary, I dare say, with the house.

The only flowers are red geraniums in tall oil jars in a row across the façade. Does the gravel sound anticlimactic? It is serene. Gardening consists of keeping it clean, dragging a sort of harrow consisting of chains over it, to efface the marks made by the boule-players. The play of light and shade do the rest.

Moaning about drought doesn’t get you anywhere, especially among friends who have just spent two weeks on Mull without a single dry hour. With 360 millimetres in the pot, moreover, we have had a fair proportion of our expected 500 mm annual allowance. So why are my arms so long from carrying cans, and why are my recent plantations so desperate for a drink?

Most of the rain fell, it is true, last winter and in July. The longest sequence of rainless days was in June and August, when the other side of the island was being soaked, but never more than 12 days or so without some dampening shower. The truth is that watering individual plants is never a substitute for

a good hou of rain. Even putting the rainmaker on is a pis aller. I suppose the reason is that competition among the congregation of roots that fills the soil. It is easy to think of plants that you can pull up with a neat tuft – but they are the minority.

Most plants insinuate their roots into as much ground as they can, whether others are occupying it or not. My can of water is the invitation to beat up the poor new boy in the class.

Is this the reason my salvias have been so slow to perform – the ones I scrounged in Scotland last summer? We paid a call to Powys Castle last weekend to see Wales’s great window-box at its most floriferous. Powys is famous for overflowing pots and vases of tender things in daring combinations, and by September all its hanging terraces, stacked below the red stone castle, bubble and froth with exotica. I drooled over it all – but especially over the salvias, in varieties I had never dreamed of, pouring down, rearing up, infiltrating their neighbours with their predictable but still somehow surprising pouty flowers in every colour from scarlet to searing blue to black and
green.

What did I do wrong? By the time mine are flowering in earnest the frost will be getting them – or even, fingers crossed, serious rain.

It is tempting to take credit for the happy accidents of gardening, to pretend that you planned a chromatic chord due solely to the almighty or (as is happening just now) the look of airy intricacy in borders buffeted by the wind.

It takes a lot to reconcile me to wind in the garden. Out in the fields I love to watch the straining grass-heads and the tossing trees. A line of Browning’s came to me just now as I climbed from the sheltered streamside out on to what passes in Essex for downland: ‘an everlasting wash of air’. Browning was in the Roman campagna where the grasses and rushes wave mile after level mile.

The border looks airy partly because I have taken the shears to tired plants with more resolution than usual, hoping for a second coming of delphiniums, thalictrums, campanulas, geraniums, valerian, even phlox. September flowers, as a result, are clear of clutter. My favourite of the moment is a clump of Francoa ’Bridal Wreath’, its white wands of flowers rising from its solid saxifrage basal clumps. Last winter nearly put paid to it; it struggled in spring, and as a result is late enough in flower to mingle with the lovely bright blue Salvia ‘Guanajato’ that is just getting into its stride. Is my Francoa sonchifolia, the default species in Graham Thomas? I think not: the flowers are pure white with none of the red spots G.S.T. mentions. Almost certainly F. ramosa.

Margaret Waterfield (am I her last fan?) in her book Flower Grouping in English, Scotch & Irish Gardens (no publisher would call a book that today) painted a group of F. ramosa with Dierama (then Sparaxis) pulcherrinia, an image that haunts me with its beauty, but I have never achieved. She says, surprisingly, that the Francoa is hardier than the Sparaxis. Watercolours like hers (the book was published in 1907, by J.M. Dent) are an almost-forgotten treasure, conveying airy intricacy, or any other happy effect, more precisely and evocatively than photography has ever done.

I was sad to read the obituary in The Daily Telegraph on Saturday for Fred Whitsey, the paper’s gardening correspondent for 45 years, who died at the age of 90.

It brought back memories of when the R.H.S. had a Publications Committee and Fred and I were both members. Those were the days before the Society went professional, as it were. Decisions were taken by committees of members, which meant in general committed amateurs, and their implementation left to the Society’s employees. We had, for example, issue-by-issue post mortems on The Garden (which was still described as The Society’s Journal). In fact the Society was just that, rather than describing itself as Britain’s leading Gardening Charity.

Fred Whitsey and I were, I suppose, the only two professional writers (he a newspaper journalist, I more of a magazine man) on the committee. We were also the awkward squad, although in my memory we were usually querying different things. Fred was a winning mixture of smile and resolve, courteous, patient and fundamentally unbudgeable. I remember (they are hard to imagine today) the discussions about advertising in the Journal: how much to allow on what subjects. I argued (goodness, I was the pushy liberal) that non-horticultural ads could do no harm. The majority seemed to think that a bank, a car maker or a jeweller would corrupt members’ morals, however much we could have spent the money on photography and writers. Fred was firm on what was relevant, tested and authoritative in pure horticulture – though if this makes him sound strait-laced and humourless it gives quite the wrong impression.

As the obituary says, no professional colleagues ever seem to have seen his own garden in Surrey. I wish I had, because a visit with him would have been an education. The departure of people like him underlines the change of the R.H.S. from a learned Society to a members’ organization almost analogous to the A.A. It is a parable of our times.

Fish (fly-replete, in depth of June.
Dawdling away their wat’ry noon)
occupy hours of my garden time. Rupert Brooke was good on fish. He must have spent his Grantchester days day-dreaming by the river.
‘In a cool curving world he lies
And ripples with dark ecstacies …..’

We moved two well-grown mirror carp from the duckpond to the much smaller and shallower Red Sea a couple of years ago, hoping that they might be of complementary genders. One hot day last week I was reading in the hammock strung between two birches by the water when I heard a different kind of splash and turned to see what looked like a whirlpool, made up of a hundred tiny carp chasing each other’s tails. I imagine they must just have hatched and were learning to swim in tight formation. No fussing from mama, though – and which of the two sleek fish calmly cruising at the far end of the pool is mama, anyway?

What happens next will be attrition, I fear. Will it be death from the skies when the heron spots them? The Red Sea would be crowded with as many as half a dozen full-grown carp. And will the resident rudd have their fins put out of joint?

Regular readers will have seen my rather shell-shocked reports of two burglaries that have left the garden bereft of some of its principal non-plant ornaments. The second and more serious raid was three weeks ago now, on the very night I went down with flu, but I’m still obsessing, above all about my folly in leaving an ideal barrow where thieves could use it. (They stole it too). Take my advice: lock up your barrows. Everything has a bright side, though, and the absence of long-familiar objects frees up some fossilized notions. I loved the armillary sphere on the front lawn of the house because it was as transparent as it was emphatic. It didn’t block the view; it seemed to focus it. Certainly without it the prospect looks rather inspid. So what shall we put in its place?

I have always loved Pope’s urn, the design done by William Kent for the poet’s Twickenham garden. It is essentially an egg with spiral fluting, two notional handles and an elegant lid. Urns certainly have funerary connotations (the word comes from the Latin urere, to burn) but Kent’s version seems more celebratory than gloomy.

We already have one in place (the thieves stole this in March, too, but we have replaced it; they’ll need a bulldozer to budge it this time). It is on the central axis of the house, beyond the duck pond, 150 yards away at the end of the park, pale against dark holm oaks. We have just decided to install another where the armillary sphere stood, close up under the windows, a strong presence in the front yard, leading the eye to its brother urn in the distance.

The central focus in the walled garden, the stolen Flora’s place, still yearns for her. The brick-paved path now runs uninterrupted from the conservatory door to the kitchen garden, under the iron pergola that was Flora’s canopy. All the perspectives are subtly altered. We have tried a ghost-like wire-work vase there, but it needs a person of a certain size, and in motion, as Flora was, to catch your eye. Or perhaps it just needs me to concentrate on the flowers and forget such showy sentiment.