Sir Roy Strong entertained the Hay Festival with an account (characteristically dramatised) of how radically he has remade his Hereford garden, The Laskett, since his wife and gardening partner, Julia Trevelyan Oman, died in 2003. Their original plantings of the 1970s succeeded splendidly in creating a formal garden in a hurry. It celebrated their joint achievements and affections with disarming enthusiasm in a series of theatrical set pieces. The Strongs planted with gusto, not quite at the nine-inch spacing of my friend Dottie Ratcliff, but looking for dramatic effects – which they achieved in record time. This was before the full menace of the now-notorious Leyland cypress was well known.

We were faced with some of the same dilemmas at Saling Hall (where I remember Roy saying, as we sat under an apple tree after supper, one evening in 1972, ‘You know, Hugh, I think you’re on to something with this gardening lark’). But wewere far less bold. It was a predecessor’s cypresses (Lawson in those days, before Leylands) that we cut down. We never got round to many necessary radical revisions of our own planting plans – even when in one case they manifestly failed. The alley of Irish Junipers that at one point was our pride and joy died bit by bit of phytophthora. It’s subtle colour and texture was simply irreplaceable, so the walled garden lost its spine. Our policy on the rest was make do and mend, knowing that nature would take its toll unpredictably, and reacting ad hoc when a tree blew down or honey fungus claimed another victim. Visitors’ eyes were, I’m sure, less forgiving than our own.

What gardener does have a Plan B – Roy Strong apart?

I suppose the best thing to do with my greenhouse in summer would be to empty it and close it down. The only plants that would benefit from it now are the tomatoes; everything else would be just as happy outdoors until autumn. I’m far from convinced that the irrigated plunge bed I’ve continued is up to its job while I’m away – which of course I shouldn’t be. It depends on a leaky pipe buried in sand on a very thin layer of drainage: a delicate balance that certainly couldn’t handle a heat wave through glass – even with the shading at its maximum.

My main concern is my not-quite-rooted cuttings (and indeed my rooted ones). They’ll go in the shade outside (there’s lots of that) with a sprinkler once a day – like the rest of the garden. It still comes as a shock how much irrigation a London garden needs. We have at least twenty little rotating plastic sprinklers branched off a pipe around the walls. Each one covers a radius of two to three feet. It is near the walls, of course, that most water is needed, where the roots of the many and various climbers are concentrated. When we’re away for more than a day or two all the pots have to be clustered together with their own sprinkler (some with saucers; some without). You can tell I’m not convinced it’s all going to work. There will be casualities.

Plants could be almost as demanding as pets if you let them. Freedom and gardening are not natural partners.

Gentiana verna at 2,000 metres. Blue is the hardest colour to reproduce, but this is not far off the truth.

Why is there no one in the Alps in June? It’s the time when the cattle make their lumbering way up to the high pastures, their heavy bells clanking. The snow is lying in disjointed drifts where the sun is slow to touch it. Everywhere else is a tapestry of the most jewel-like of flowers, embroidering the lush new verdure of the middle slopes or piercing the brown grass above the tree line, where mats of rhododendron and juniper are stirring in their winter sleep.

First come tiny ivory crocuses and the fretted furry leaves of the pulsatillas, Anemone sulfurea, soon followed by its wide, candid, creamy flowers. Gentians are already flowering: the deep violet trumpets of G. clusii and the brilliant sapphire stars of G. verna. There are violets with big flat faces, a little pink thlaspi in the middle of a stream, small purple orchids, soldanellas with pale violet fringes, lavender-coloured centaurea, primulas very like cowslips, shiny yellow globes of trollius, starry arabis, harebells, pale thrift, miniature alchemillas, many spurges and the rich blue heads of a rampion, Phytheuma orbiculare, which I took for a very special clover in the long grass – and which I now learn is an emblem of Sussex.

All these on a single ramble in the Val d’Anniviers in search of what is said to he the most splendid old larch in the Alps. Alpines are not my natural territory. I expect all my plant names have been superseded long ago; my authority is Correvon’s beautiful Alpine Flora of 1911 and its art deco botanical paintings by Philippe Robert.

We found the larches, cohabiting with equally tall and craggy Arolla pines, perhaps twelve feet round and sixty or seventy high, punished by blizzards but waking fresh in the chilly sunshine. The tender first larch leaves springing from old fissured brown wood are as touching and inspirational as the most exquisite of the emerging flowers.

Not a soul about, apart from some mountain bikers on terrifying trails. The hotels are nearly all shut; the skiing is over, the summer holidays still to come. Yet in the weeks between the flowers appearing and the cows eating them (or have the cows the perspecuity to steer around their favourites to leave them to seed?) the sun is bright, the air still cool enough for long walks, the Alps are at their best.

A brochure worth a medal

“A younger look” we were promised in the show gardens at Chelsea this year. How we would recognise it I’m not sure. The look that struck me was a distinct taste for (indeed a heavy dependence on) the lightweight charmers of spring. Perhaps less (though not much less) use of white foxgloves, but complete abandonment, in some cases, to such wildlings as sweet rocket, buttercups, ferns, campion, alchemilla mollis, vetch, verbascums, various feathery umbelliferae. and almost universally Iris sibirica. The flowers were lightweight, but the supporting trees, it seemed to me, heavier and more numerous than ever. There was no questioning the charm of such stylized meadows, but where have the mainstream garden plants, the long-term stalwarts of the border, bred over centuries to be unlike wildlings as possible, disappeared to?

The answer in some cases is the marquee, where the specialists display their thoroughbreds. It was worth braving the throng for Hillier’s stand alone. Never was the Monument more monumental than in this bravura performance of tall trees, exceptional shrubs and witty variations on a dozen different colour schemes; Hillier’s 69th Gold Medal in a row. Trad’s own coveted Annual Medal ended up, after much debate, with Rickard’s bosky display of ferns, from trees down to microscopic beauties. The idea dawned, then and there, of turning the always-shady end of our garden into a fernery.

Perhaps not for display of plants, but certainly for its imagination and conceptual unity, Trad rated Alan Titchmarch’s Britain in Bloom garden as high as any. He managed to encapsulate, on a cramped triangle of a site, the British landscape from the highlands to the Scilly Isles (or was it Yorkshire to the Isle of Wight, Alan’s own trajectory?) A brook tinkling over a mossy stone wall flowed almost believably down to the sea, a beach and beach hut and the plants of summer sunshine. A tour de force.

And equally memorable, but moving too, was No Man’s Land, a First World War memorial in plants, designed by Charlotte Rowe for ABF, The Soldiers Charity. The descriptive booklet, with flower paintings by Irene Laschi, deserved a medal for the best piece of print offered to visitors – possibly ever.

Rhododendron augustinii at Cae Gwian, planted 15 years ago. The dim light is part of the point. So is sunlight

Just home from our first visit to the Welsh woods since the near-hurricane on Valentine’s Day. The funny thing is that trees never fall in predictable ways. There seems no reason in the mess of often criss-crossed trunks. I like the French forester’s term for it, ‘chablis’ – perhaps because it makes me think of a cool beaded glass of something on the green side of gold.

You’d expect most of the damage to be on the windward edge. Often it is scooped out of the middle of a plantation. Worse than the loss of trees is the muddy chaos where the harvesting machines have to shuffle to and fro bringing the timber out to the roads where lorries from the mills collect it (in 25 ton loads, not greatly appreciated by motorists on the narrow winding roads.) Happily there is a demand for the massive spruce logs,16 feet long. House-building must be picking up.

It rained all the weekend. But whoever said there is no such thing as bad weather; only the wrong clothes, had a point. Slipperiness is the main problem: you feel constantly in danger of falling over. Also rain on your camera lens – because curiously. I have an urge to take photos in the low light. Colours are saturated and the lack of shadows gives a different value to what you see.

Best of all were our blue rhododendrons, hovering over the bluebells under the pale green of beech and larch in fresh leaf. In the rain their purply blue took on a savage intensity, while in the distance they were insubstantial wraiths.

It was a poor weekend for the National Gardens Scheme. We were almost the only visitors in a garden in Dolgellau that deserves crowds. Craig y Finnon is the garden of a fine Victorian house restored by its plantsman owners, Jon and Shàn Leas. There is exquisite precision in their gardening, whether formal in box hedges or spreading among massive rocks where azaleas and alpines cohabit under splendid old trees with moss and ferns. Royal ferns sow themselves in the rocks and send up shoots like bishops’ crosiers. The black slate drive was filled with pink flowers falling with the rain from arching rhododendrons. It was a moving visit, seeming to encapsulate a century and a half of skill and devotion to the perfect plants for a dramatic site.

The existence of Hillier’s nurseries has always been a given in my gardening life. Of course I realised, when I began to collect trees in the early 1970s, that we were incredibly lucky to have a single source for almost any tree or shrub we had heard of. And what’s more a reliable one, whose plants actually corresponded to their labels. At one time I was ordering and receiving thirty or forty at a time, sometimes with apologetic little notes saying I might have to wait a year or two. They were so healthy, in the main, that one didn’t stop to think of the miracle of logistics involved, getting them together from several separate Hampshire fields. A story went that one customer telegramed ‘Plants arrived safely. Presume roots follow’ – but that must have been some other nursery.

Now I am thrilled to find that the Hillier history has just been published. Discussions about a possible writer had been going on for several years. In the event they have found the ideal person – in the bosom of the family. Jean Hillier is Sir Harold’s daughter-in-law, married to his younger son Robert. She has produced as attractive a family company history as I have ever seen, gleaned from archives going back beyond the date of founding, 1864, and packed with family lore, records of rare plants, ingenious propagators, the constant hunt for more nursery land and above all the extraordinary personality of the third Hillier inheritor, Harold, surely the greatest and most driven plantsman of the 20th century.I was starting work on my first tree book in 1972, luckily for me at the very moment when Hillier’s Manual appeared. Is there a gardener who hasn’t handled this astonishing production? Does any other craft or trade have a catalogue/bible like this? It is effectively Harold Hillier’s life’s work between covers, put there, largely, by an extraordinary young man, Roy Lancaster. My original dog-eared copy, bought the year we moved into Saling Hall, sits where it always has, within reach of my desk – now with its current, more grown-up successor smartly bound by its side.

Jean Hillier weaves many of the threads of a century and a half of garden history into a story that kept me engrossed over a whole weekend. The climax, in one sense, comes when Harold’s dream of a complete arboretum open to the public comes true. In 1977 Hampshire County Council, after some persuasion, accepts the ownership, and the responsibility. It is a time I remember vividly: negotiations were iffy. I had the idea (this is not in the book) of introducing another great Hampshireman, John Arlott, into the discussion. Arlott was of course the voice of cricket, with a vast audience for his Hampshire bur. He was also mad about wine, a keen collector and the wine correspondent of The Guardian. He lived at Alresford. I asked him over lunch one day if he was keen on trees. ‘Love ’em ‘ he said. A few weeks later we went to lunch together to Jermyns. He and Harold found they had more in common than you might think. I don’t know what John said to whom at the county council, but it can have done no harm.

Holland Park (on a dull day)

I didn’t know, when we left our garden after 40 years in March last year, how much or how little I would miss it. Now I do, to my surprise: very little. I am far busier than I expected in our new little patch. What I didn’t expect, though, is quite how much pleasure I would get from other people’s. Perhaps ambitious gardeners (or those with big gardens) get too self-centred. Perhaps not only ambitious ones. I fear I used to tick off plants or other features in other people’s gardens if I either had them already or wished I did. No more.

I am avid for the front gardens I pass, nosey about back gardens and besotted with the two gardens I visit most often: Holland Park and Exbury.

Holland Park is easy: barely ten minutes walk up the road. “Park” barely does justice to an estate in the heart of London that includes formal gardens on the grand scale, one of England’s biggest and best Japanese gardens, a fine camellia collection, an arboretum with woodland walks, a summer opera house, a sports field for football and cricket and tennis, an outdoor gym, an ecology centre, and a substantial wild area, now full of bluebells, where trees can fall and be left to rot (and no doubt foxes multiply).

Holland Park’s tulips (40,000 were planted for this season) are rightly famous. Their colours gradually evolve from March to May, starting pale and pretty and intensifying to the gayest Joseph’s coat you can imagine. Every day sees a subtle shift in the palette.

As it does at Exbury, but on a scale no one can take in without repeated visits. This is now the third and fourth generation of the de Rothschild family to nurture their 200 acres on the Beaulieu River, where it flows into the Solent. In their maturity they are, I’m afraid, awesome. Every walk is a discovery and leaves my head full of questions. How I wish I knew rhododendrons better – but camellias, too, and magnolias, and all the exotic wonders the Rothschilds have collected.

My trick is to consult the website the day before I go. John Anderson, the head gardener, posts the plants not to be missed on his Noticeboard. Hardly a substitute for knowledge, I know – but a real help in acquiring some.

The drone of a lawnmower blends withe the burbling of a diesel on the harbour. The smell of mown grass mingles with the marine smell of mud and seaweed .I have temporary charge of a different kind of garden; a walled yard only fifty yards from the sea, where frost is unlikely but the wind is a constant presence. The walls give it more shelter than its neighbours, but the air is rarely as still as it is today. Indeed the pines and macrocarpas and holm oaks planted to shelter the seaside houses are in a sorry state: last winter’s gales burnt them a depressing brown. Some of the macrocarpas should be put out of their misery.

Most of the garden is paved, with slight changes of level giving raised beds. The planting is mostly low-growing, and today, with masses of aubrieta, pink and pale mauve, with iberis and a clump of lithospermum (lithodora if you prefer) starting its sharp sapphire stars, with forget me nots and a tiny pale pink geranium, it is almost convincing as a natural seaside happening. In a wall corner a choisya is entirely covered with its white flowers. Bluebells and borage have invaded a taller side border yet to flower. I have trained the long shoots of a rose, Madame Alfred Carrière, along the whole length of one side. A little wooden pergola will be nearly crushed by the end of summer under campsis, clematis, honeysuckle and a pink everlasting pea.

Last summer, with a meddlesome itch to add what the trade calls ‘accents’, I added a few plants of Verbena bonariensis and the silveriest of elaeagnus, a little multi-stemmed tree from Cedric Morris’s Suffolk garden. I remember how his walled garden had few vertical features. Irises of course – and this one little tree. Benton End was a much-travelled garden: Morris was always giving his plants away. His legacy lives on in glory at Beth Chatto’s. And much more modestly down here on the Solent.