Are we making the most of what water we have in our gardens? Here is Celia Fiennes, a gentlewoman garden-touring in the 1680’s, describing Wilton House.

‘…the river runns through the garden that easeily conveys by pipes water to all parts. (A) grottoe at the end of the garden…. its garnished with many fine figures of the Goddesss, and about 2 yards off the door is severall pipes in a line that with a sluce spoutts water up to wett the Strangers; in the middle roome is a round table, a large pipe in the midst, on which they put a crown or gun or a branch, and so it spouts the water through the carvings and poynts all round the roome at the Artists pleasure to wet the company; there are figures at each corner of the roome that can weep water on the beholders, and by a straight pipe on the table they force up the water into the hollow carving of the roof like a crown or coronet to appearance, but is hollow within to retaine the water forced into ti in great quantetyes, that disperses in the hollow cavity over the roome and descends in a shower of raine all about the roome; on each side is two little roomes which by the turning their wires the water runnes in the rockes you see and hear it, and also it is so contrived in one room that it makes the melody of Nightingerlls and all sorts of birds which engaged the curiosity of the Strangers to go in to see, but at the entrance off each room, is a line of pipes that appear not till by a sluce moved it washes the spectators, designed for diversion.’

Have we lost our sense of humour?

There’s a moment at the beginning of August when the big bush or little tree of Solanum rantonettii scatters its crown with purple potato flowers. Only little ones – and I’m never sure whether to say purple or blue. It’s a matter of judgement -or maybe eyesight. But a fifteen-foot dome of this colour pretty much takes over the view for six weeks or so.

No such luck with it in Hampshire; it can be too cold even a mere two miles from the sea. But for a London garden with some wall shelter and a fair amount of space I can’t think of a more satisfactory little tree. I tucked it into the south-facing corner by the greenhouse door. Now we have to cut off six-foot shoots to stop them casting the greenhouse into shade.

My obsession with blue has its moment at this time of year, and the solanum has a companion little tree in a pot on what I call the quarterdeck, four steps higher at the far end of the garden (for its total length, think a cricket pitch). I use blue in what a grammarian would call ‘sensu lato’ – as one must in discussing a colour that ranges from summer skies to deep distant shadow. Little acnistus (or iochroma if you prefer) dangles inch-long flaring bells of a deep violet hue. I keep this little standard clipped lollipop style the better to see its bells.

The most obliging blue, particularly eager to oblige, scrambling through the border, is Geranium ‘Rozanne’, celebrated last year as the ‘Plant of the Century’ or some such. With clematis ‘Perle d’Azur’ the blue mood needs lightening. Phlox ‘White Admiral’ is the answer.

Since I first saw the scarlet fairy bells of Fuchsia magellanica years ago in its native Patagonia I have loved this modest beauty. When years later I met its albino version I loved it even more, and have planted it wherever I have a spot in the garden that needs a quick and charming lightweight. Then I came across ‘Hawkshead’, a lovely purer white version. I have a tall plant of ‘Alba’at the far end of this little garden, doing its best to block the steps up to what I think of as the quarterdeck. I regularly have to cut off some of its spreading branches; it rapidly adds more on top. It’s certainly taller than me now, an airy tower of tiny dangling bells on the blush side of white.

The contrast with the pure white of ‘Hawkshead’ is telling. I don’t plant many duplicates; I’m too keen on trying new things, but there is the pleasure of subtle variety here.

In the last few days, down by the Solent, I’ve seen more samphire than plants with RHS approval, but I always associate seaside summer with the combination of hydrangeas, usually in a washy pink, with the scarlet shock of montbretia. They are far from being AGM plants, but in bright light and salty air they make a strong holiday statement. Fuchsias love it here too. The other day in a garden by the Solent I saw a hedge fully seven feet high of the original red-flowered variety, the red not strident but just lending it a glow. It’s a splendidly biddable plant: cut it tight or let it gesticulate, a midsummer joy that keeps going well into autumn.

We landed in Normandy on D-day, eighty years after the event, to find jeeps clogging the roads, a sea of ancient khaki uniforms and veteran Dakotas roaring over the surf. But it was another British connection that brought us; we came to revisit the most beautiful English garden in France. How many people know that one of the best of the famous collaborations between Gertrude Jekyll and Edwin Lutyens is on the other side of the Channel? Literally ‘on’. The thirty acres of Le Bois des Moutiers tumbles dramatically down to a cliff-edge and the sea. The garden, and one of Lutyens’ most successful country houses, was commissioned by the Mallet family of bankers at the end of the 19th century. If you book a visit there is still a member of the family to show you round, though today it belongs to the Seydoux, owners of most of France’s cinemas. In 130-odd years it has matured into something that would give its planters justified joy.

Lutyens hit mid-season form with the house; serenely simple at first sight but with precise details that sometimes seem to refer to Gaudi. The partnership with Jekyll gives the surrounding more or less formal gardens complete authority; it is hard to imagine them being otherwise. To the south they melt into orchards, then reach the edge of a slope that comes, in what in Devon would be called a combe, down to the cliff edge far below and what the French, with perhaps unintended poetry, call ‘le grand large’.

The garden, and Vasterival, another woodland treasury of plants created in the 1950s by Princess Greta Sturza, a former Wimbledon champion, face each other across the valley above the sea. The little village of Varengeville, south of Dieppe, is known for its cliff-top church with a richly blue stained glass window by Georges Braque. And inland lies the pastoral Pays d’Auge, source of butter, cider and Calvados.

Sod’s Law visits Chelsea. Monday, Press Day, the royal inspection and the only time you can wander in relative ease round a show without a crowd, was a perfect summer’s day: light sun, a faint breeze under a cloudless sky. Tuesday; cool, sky grey and drizzle turning to rain.

There are fewer Show Gardens than in the past, but one or two were memorable. Trad’s Garden of the Show rarely chimes with the official judgement; it’s the same with wine ratings, but then I’m a heedless hedonist. My favourite was the Roman villa, complete with attendants (not, I think, ‘enslaved persons’) in togas. I don’t know whether the water dripping quietly from the eaves into a marble channel in the floor was really a Roman trick to cool the loggia, but I hope so. (By Tuesday of course it was unneeded; the heavens did the job).

The actual gardens, to my taste, were predictably more about ‘sustainability’ than beauty – or even use. I suspect Tom Stuart-Smith will be rated one day as the Repton of our time: his touch is so sure, authoritative, stylish but somehow realistic and comfortable. His palette this year was calmly green and white, with some purple for contrast. His biggest plants were, of all quiet things, three ordinary hazel bushes of significant size. A substantial wooden hut, a stone water tank and a cluster of clay pots set the tone of almost humdrum existence heightened by intelligent, rather than eye-catching, planting.

There are some colours that burst on us once a year, without precedent: unique, exciting and transient. The new leaves of lime trees have the stage this week; a colour that by coincidence we tend to call lime-green – referring, though, to the citrus fruit rather than one of our champion park trees. Each April I amble round Kensington Gardens, pausing at tree after tree to enjoy the glowing tenderness of the unfolding buds, the little shining package of the leaf pushing out, limp for a day before breathing gives it strength to open to a pale green oval.

Limes were the chosen show-trees of the Georgians. They imported them in thousands from Dutch nurseries to plant their avenues. Kensington Palace has a great crinoline of them centred on the Round Pond, planted perhaps by Queen Charlotte, replanted in the past twenty years or so and now brilliantly verdant, the epitome of a stately spring.

Our little box hedges seem to be almost the last of this threatened species in the neighbourhood. The box moth caterpillar or the blight has either put paid to the rest or their proprietors have despaired of their survival, rooted them out and planted one of the proposed substitutes. Rassells Nursery just across the road follows RHS advice and proposes Ilex crenata, which superficially resembles box. Some nurseries have even cooked up a cunning new name and sell the little holly as Luxus.

It has an upright growth, unlike box, but can be clipped to grow into a flat-topped little hedge that will grow (they say) no faster than box. It may not be as tolerant as box to either drought or too much moisture but is apparently subject to a nasty-sounding black root rot. Nor does it have the slightly foxy smell in the rain that some people hate (and I find part of box’s charm).

For myself, I will go on defending our box hedges, the very definition of our garden, while I can. We use moth-traps and Py spray. We pick off the caterpillars and squish them as soon as we see them. I fear it can’t go on for ever, but while we’re around our box will have all the protection we can give it.

Sixteen degrees on February 16 doesn’t sound or feel right. The magnolia in the front garden looks ready to burst its buds. Primroses are even fading on the north side of the house. Daphnes are in full fragrant flower and the flowering currant is already giving off its Marmite smell. Camellias are in full bloom and in the water tank the fish look distinctly frisky.

Last night we slept with the French windows open. We see summer blouses on the street. The weather forecast shows no hint of winter returning to duty. Should we be alarmed? And is there anything we can do?

The horticultural answer is yes: take advantage. And take precautions. Bring the swelling buds into the house to enjoy them, and try to stop the greenhouse from becoming a hothouse by shading during the day and ventilating day and night.

Now its February 20; the mercury has dropped three degrees and low clouds have hidden the sun. The magnolia has shed all its furry bracts, leaving its purple flowers closed but naked like dark flames among the grey branches. The cercidphyllum that hangs weeping over the pavement is opening its first tiny heart-shaped leaves at the tip of each branch. Crocuses that have found their way into the front garden beds are starting to clump up and a fresh crop of purple flowers are pushing up through the tangle of leaves of Iris unguicularis. It’s a badly designed plant; its leaves succeed in hiding its flowers.

A fat bag of mulch has just arrived form Rassell’s nursery across Earls Court Road. Spreading it is my next job.