'Prince Charles' smothers a bay tree

The walls are the real driver of a little London garden; you see more of their surface than the diminutive beds. Walls, and pots. I counted just now: we have sixty two planted (not including the green house). Yes, it’s intense; it needs a lot of watering, prinking, daily adjustments. But what else does a gardener want to do? Go abroad, sure. Visit other gardens. You need friendly neighbours and willing helpers. So far, so good. And we’ve learned that a happy climber is worth any number of pots.

This spring I went back to clematis. I’ve seen them in the past as the cherry on the cake; an extra touch of colour on something more structured and essential. What isn’t essential, though, in a garden you can take in at a glance? The trellises that carry the walls up another four feet are the backdrop to all the planting. Neither we nor our neighbours want transparent walls.

One trellis panel has always been bare. There is a mere scrap of bed below to plant in. A Cotoneaster horizontalis reaches up gamely above the wall, but seven feet is a fair stretch even for this marvellously accommodating plant. I’ve heard snide comments: it’s boring, vulgar, even ugly in its fishbone formation. Rubbish: it’s vigorous, designed like no other plant, bright in spring with little white flowers and in autumn with red berries. A little pruning will even make it turn corners. Something evergreen, and rapid, was what we needed to grow through it and on upwards.

Eventually I worked through the options to Clematis armandii, the Chinese evergreen that can become a matted mess if you let it. I won’t. Early progress, though, has been frustrating. Its first long shoot shot up, but not till summer and was still unripe when frost came. It perished. This year three shoots managed five or six feet in April, then stopped. When does it want to grow?

This year’s success has been a lemon-peel clematis, C. tangutica ‘Helios’. The corner by the greenhouse has been more than filled by what the vulgar might call a potato-bush, the purple-flowered Solanum rantonnettii, a cutting from our daughter’s garden in the South of France. ‘Not quite hardy in Britain’ say garden dictionaries. ‘Rampant in London’ say I. It waves slender shoots in full flower, purple on green, high above the greenhouse. Just the place, thought I, for a yellow-flowering clematis. And up she goes.

Rose ‘Bantry Bay’ is the climbing frame for the lightning-fast Clematis viticella ‘Kermesina’ – too red, perhaps to be cheek by jowel with a pink rose. Then I think of Matisse. Two more viticellas scramble with abandon up and through the tangled ivy and Hydrangea petiolaris on the right hand trellis. ‘Polish Spirit’ is a deep, almost brownish purple, hanging in swags. Two or three weeks later comes C. ‘Alba Luxurians’ with its odd white-and-green flowers (or sepals, to be pedantic).

Two other slightly larger-flowered varieties keep the season going: the peerless Perle d’Azur and Prince Charles, like a paler, slightly anaemic version. Oh, yes, and I planted C. wilsonii, like a rather late C. montana, to light up Hydrangea petiolaris on the wall before its turn comes. Finally, to complement an apricot-coloured Chaenomeles I don’t much like, the blue C. alpina. Next year I expect I’ll find room for more.

Box problem captioned by John Henslow

The ancient Romans had box bug problems, too. No sooner had I written my recent column on the menace of the box-eating caterpillar than I paid a visit to the new herbarium at Cambridge University’s Botanic Garden to be shown, by its curator, Christine Bartram, a box shoot under attack – two thousand years ago. John Stevens Henslow, the creator of the garden, found it in a Roman tomb at Chesterford, near Cambridge, in the 1830’s.

It is difficult to overestimate the influence of Henslow, as a scientist (indeed the very word ‘scientist’ for what had been up to then called a ‘natural philosopher’ was coined by one of his colleagues.) Henslow was Professor of Geology, then Professor of Botany in the University. In the 1830s he developed the new, much bigger botanical garden in the country a mile from the first.

His particular interest, in fact his obsession, was the question of what constitutes a species (and what a variety). The religious view (he became a clergyman) was that God’s creation was, you might say, specific. But when he took his pupils round the countryside collecting herbarium specimens their primroses (for example) were not all identical.

He wondered what this  meant. In planting the botanical garden he went further: there is still an imposing group of Pinus nigra as he planted them, specimens from Corsica, Austria and the Crimea: the same species with quite different habits of growth.  All this was in Charles Darwin’s mind when his tutor, Henslow, declined a berth on the Beagle and nominated Darwin to go in his place. It was the origin of The Origin of Species.

Darwin gave his herbarium, collected on the five years voyage, to Henslow. The university has held their two herbaria, along with, for example, John Lindley’s, for getting on for two hundred years. Then came John Parker, director of the garden from 1986 to 2010. He was determined to tell this story and give the university’s unique herbarium a fitting home. I was briefly involved in a fund-raising campaign (the garden had no public building or education space in those days). I remember our application to the Heritage Lottery Fund was turned down (not enough buses from surrounding schools, if I remember right). The Fund’s offices were two streets away; in summer its staff ate their sandwiches in the garden.

What small beer our fund-raising efforts became, though, when the munificent Sainsburys appeared on the scene. Their Gatsby Trust (the Fitzgerald link eludes me) very much got the idea. It sees Cambridge (with the Wellcome DNA institute nearby) as the world centre of genetic studies. £82 million later the result is a laboratory building like no other, in the garden, a splendid affair of stone and immaculate concrete, to house the iconic herbarium and related studies (also a cafe and facilities for public education). The box? It still has problems.

A sycamore is nobody’s first choice of a tree for a small garden. It’s messy in spring with drifts of pollen and the detritus of flowering. Then comes the sticky deposit of aphids and deep summer shade. The autumn leaves, curling and brown, form useless piles; and far worse are the seeds, obscenely fertile, germinating like grass in every chink of soil.

But we have a big one, seven feet round and fifty high, and no seedlings. Come to that, no flowers. We respect it like a London plane, light up its peeling trunk at night, and suffer its shade – if not gladly, at least patiently. What’s the trick?.

See if you can understand this account of its sex life. “Most inflorescences are formed of a mixture of functionally male and functionally female flowers. On any one tree, one or other of these flower types opens first and the other type opens later. Some trees may be male-starters in one year and female-starters in another. The change from one sex to the other may take place on different dates in different parts of the crown, and different trees in any one population may come into bloom over the course of several weeks.” (This comes from Wikipedia).

Part of the answer is in its fashionable hesitation about its gender. If only it would decide to be a boy how happy we would be. But the main reason it lacks a sex life is that we prune its shoots back brutally every winter to limit its spread over other people’s gardens (and our own). I suspect its wood never ripens enough to get to the flowering stage. It’s an expensive solution.

Trad's choice: wide

“Best of Show’ is always a well-debated subject, and Trad’s annual Chelsea award, over several decades, has not always coincided with the official verdict. This year my friend James Basson, who scored so highly last year with his delicate evocation of Provence, was given the gong for his Maltese quarry. It was a memorable image, dominated by its ziggurat or cenotaph, but how it qualified to be called a garden I’m not sure. The plants were chosen with absolute botanical rigour, but I fear most of them were what friends call BIO (for Botanical Interest Only). Perhaps the spec for entries doesn’t mention ‘garden’, though heaven knows it’s a broad category. Sadly there was less competition than usual this year: the RHS had to fill the empty spaces in the Main Avenue (and frequently elsewhere, even in the Great Pavilion) with champagne bars.)

Trad’s Best of Show was tucked away among the ‘Artisans’, by the woodland picnic area in Ranelagh gardens. I’m afraid most visitors will have missed it. A pity; it was a piece of Japanese artistry worth going a long way to see, and almost never seen outside Japan. The designer, Kazuyuki Ishihara, has won gold here before, but this year’s tiny jewel was exceptional, in concept, in truthfulness, in precision and in expressing such a love for its materials that I found it moving. Even the back of his stand was exquisitely gardened.

The other moving moment of the day was Michael Heseltine’s speech at the President’s lunch. He started ominously by telling us there were no jokes coming, then in ten absorbing minutes told us why gardening matters and what we should do about it. In a sense we have heard it all before. Give a schoolchild a bean and they will never forget seeing its first leaves pop up. The moral effect of engaging with the natural world.

‘Gardens’, he said, ‘in whichever form, are expressions of ourselves. They are statements of pride and responsibility. They are definable spaces often requiring easily acquired skills. They provide talking points for communication with neighbours. They impose a year round discipline. They provide a therapeutic escape from daily pressures.’

Lord Heseltine has worked hard and persistently on the revival of communities gone to the dogs. He has huge experience in the hard slog of restoring hope and pride, work that is long on boring admin, tricky politics and often slow returns. He is totally convincing on the need for life-changing inspiration, hard to conjure, patchy in its results, but vital in ‘helping people feel a sense of purpose, an interest in what their life holds. There are no simple answers to complex questions, but gardening can play a part. Derelict land is all too present. Provide them with the tools to plant it. If they plant it they may feel a pride in what they did. They may wish to defend it, even extend it. The work requires little skill but it offers ladders.’

His sentiments and a piece of loving artistry made me leave the showground with a sense of fulfilment – and a sense of purpose.

Trad's choice: detail

Should I have got my camera out before the rain?

The garden has just been soaked, almost drowned, for the first time in many weeks. I was out before breakfast emptying saucers and discouraging snails. Relief was written on every flower’s face.

The picture last week when we arrived in Wales was very different: the hills were an unaccustomed shade of khaki, the silver streams switched off. The next day we were at Bodnant when the heavens finally opened. Somehow the scene changed from beautiful to magical in the rain. We had not been there for four years (all wrong, since our woods are only 50 miles away). How could we have stayed away from Britain’s/Europe’s/the world’s greatest gardening treat?

The National Trust has been shrewd enough to make Michael McLaren, son of the third Lord Aberconway, for many years President of the RHS, Director of the garden. How he keeps all 80 acres, so densely and intricately planted that it feels like 200, in his memory I can’t imagine – though he has, of course, known it all his life. It was a privilege to be shown round by someone who can tell you the past, present and probable future of every corner.

Large parts of Bodnant are seriously steep. I have never really fathomed how the area of a steep slope is measured: is it the surface as seen from the sky or from a point at right angles to the slope? As contour lines crowd together on a map I suppose it must be the latter. It makes a difference when you are planting – or indeed weeding. In any case it’s a big 80 acres.

Furthermore the area of tended garden, accessible, nurtured and with all its plants labelled, is rapidly increasing. The hillside opposite the house, across the little river Hieraethlyn, had seemed a garden too far for many years. Now it is very much part of the tour, with generations-old specimens on show again and lavish planting between.

The famous laburnum tunnel is apparently the feature than attracts most visitors. Its long yellow curve was just beginning to light up. What I had almost forgotten, though, was how grandly the wide terraces descend westwards from the house, embracing more and more of the sublime landscape, claiming and pulling in the Carneddy mountains across the Conwy valley as part of a stately, unbelievably ambitious plan.

There is a phase of momentous tranquillity when you reach the vast canal terrace with the prim and pretty grey-and-white Pin Mill to the left, almost too pretty and party-dressed for such an elemental prospect. Then you are precipitated among soaring trees and dazzling flowers deep into the quiet dell, to hear the river chuckling by and follow it for a good half mile, in awe of forest giants and enraptured by the glow of flowers.

The plant of the moment at Tresco, if I had to choose one, was the echium from Madeira, Echium candicans. When it was accompanied by the monster geranium from Madeira (G. maderense is happily naturalized on the islands) the sight was one of the most splendid in gardening.

I believe I’ve hinted, over the years, at my faiblesse for anything blue. Unconsciously I seek out blue flowers in gardens. In nurseries I head straight for the blue plants. It is a minority colour; there are ten pink/mauve/reds and maybe twenty yellows to each blue – and true blue, in the range you might call French, butcher’s or sailor’s, is rare. Ceanothus gives us some pretty punchy deep blues; hydrangeas tend to wobble between blue and pink. Borage is a clear lightish blue…. but its subtropical cousin, Echium candicans, is the real deal.

The Scillies are mild enough to make a shrub of it. It would struggle in most places on the mainland. Its cousin E.pininana can get close, as an almost ridiculous spire, for a year or two, though often wandering from blue towards red. Its other equally lofty cousin, E.wildpretii from Tenerife, lets the side down by being red, thus of scarcely more interest to my blue-besotted eyes than a red delphinium.

On a visit to Cambridge the other day, though, I had a 60 volt shock. One of England’s most photographed walls is suddenly under siege from with echiums. The splendid sandstone flank of Clare College, the left hand part of that view of King’s College that symbolizes King’s, Cambridge, and sometimes even England on calendars, is a frenzy of flowering spires.

The enterprising head horticulturist at King’s College, Stephen Coghill, spotted a perfect south-facing site for his seedlings of E. wildpretii and E. pininana, the soil essentially gritty hoggin, and seized the chance. Almost incredibly, 18 months later, the seedlings, planted out in April last year, tower over seven feet high. Maybe one day E candicans?

Tresco: shadows in a corner

An ambition achieved: for years I have wanted to visit the legendary island of Tresco, to see its garden of all the things we can’t quite grow anywhere else in Britain. Somehow the journey to the Scilly Isles always felt like an insuperable obstacle. Resolve arrived this spring. The ‘transfer’, as a travel agent would call it, was an entertainment in its own right: 7. 06 at Paddington, 9.45 at Exeter St David’s: an hour to visit the startingly beautiful cathedral (which by itself made the whole journey worthwhile), 11.45 take off from Exeter Airport in a Skybus Twin Otter, 12.20 land at St Mary’s and 1.15 catch a launch to Bryher.

Bryher is the nearest of the Scillies to America, England’s westernmost habitable point, a tiny island just west of Tresco. At night its rocky reefs and peaty downs are swept every half-minute by the beam from the lighthouse on Bishop Rock, the starting line for liners challenging for the Blue Riband of the Atlantic. Bryher also boasts the Hell Bay Hotel; extreme comfort roguishly named after a sailor’s death-trap, a reef-rimmed lee shore notorious for shipwrecks.

The islands were serene, the sea a glassy azure, the air cool and the sun bright when we took the five-minute boat ride to Tresco’s tiny village. No sign of the famous garden except, peeping over a low hill, tell-tale tattered tops of tall windbreak trees. Only long-serving Monterey cypresses have that ragged silhouette. Twenty minutes walk brought us to the garden gate – and another world.

We were in the horticultural equivalent of a fancy dress ball. The climate is sub-tropically benign, insulated by the Gulf Stream. It can very occasionally break down, as it did in 1987, when frost and snow destroyed all the tender plants, and in January 1990, when a hurricane felled most of the 130-year-old shelterbelt and almost all the biggest trees. The epic story of recovery from these disasters is told by the head gardener, Mike Nelhams, in Tresco Abbey Garden, a Personal and Pictorial History. I don’t often give ISBN numbers, but it’s worth it for this eye-opener: 978 185022 200 2.

I found myself floundering with many of the genera, let alone the species, of the plants in his lists. Aeonium with its varnished maroon leaves, Banksia, Beschorneria leaning lasciviously, Bomarea, Carpobrotus, Coleonema, Doryanthes, Dryandra, Fascicularia, Furcraea, Kunzia…. The impact of so many strangers at once is overwhelming. It was almost a relief, after an hour or two of wandering through such a brilliant palette, to emerge to the quiet beauty of gorse and campion and bluebells and wild garlic lining the island’s narrow lanes.

Tresco Abbey Garden, we learned, was begun in 1834 by Augustus Smith from Hertfordshire, the heir to a fortune, who leased the island from the Duchy of Cornwall and became Lord Proprietor – as his great great grandson Robert Dorrien-Smith still is today.

When the Smith family arrived they found the remains of a Benedictine abbey in the most sheltered spot on the island and built their house beside it. It remains a sequestered place, shaded by New Zealand tree ferns, while the dazzling profusion of the Mediterranean, South Africa, Australia, Mexico and Chile spreads up the hillside above in a pattern of paths and steps and pools reminiscent, in places, of its Riviera contemporary, the Hanbury Garden at La Mortola.

The Dorrien-Smith family have persevered for nearly 200 years, living on the island they rule, loyal to a marvel of horticulture which is entirely their invention, and still bursting with innovation, new ornaments and new plants.

The depredations of the boxtree caterpillar, Cydalima perspectalis, have reached such a pitch in Kensington that Rassells Nursery has stopped sellling box plants for hedges. Instead they are offering a miniature holly, Ilex cornuta ‘Luxus Globe’,

Its leaves are smaller and darker than box. Its paler new growth at this time of year is quite pretty, but no one can pretend it will ever be a substitute for the mainstay of garden design for, literally, thousands of years. The Romans relied on it. Pliny the Younger cut it into extravagant figures at his villa by the sea. Populations of box trees are often evidence that Romans colonized a district. Where we lived in the Auvergne the outlines of a Roman town were still just visible, but the valley below was thick with ancient box trees. You didn’t find them anywhere else near there.

We all know its qualities as the trim and malleable friend of gardeners in the European tradition. Not everyone likes the evocative small of a box parterre on a dewy morning in summer, but the thought of a unique tradition chewed to oblivion to feed a nondescript little moth is hard to stomach.

We are defending our little hedges with whatever treatments are allowed. The caterpillars last year arrived in August ; in this strange spring they became obvious in chewed leaves and tiny webs in late March. The tiny caterpillars are hard to find but munch alarmingly fast. Even with daily inspection some survive – and turning your back to go away for a week is seriously ill-advised.

Ash trees, even elms, can be replaced with other trees, however we may miss their familiar silhouettes. Box, alas, has no real substitute. At Wisley there is a bed planted with possible replacements, trmmed as low hedges ; none, I fear, really cuts the mustard. Perhaps the best is Teucrium x lucidrys, or by its medieval-sounding name of hedge germander. The Prince of Wales evidently thinks so ; he has replaced box with it at Highgrove. Its chief drawback is its spikes of pink flowers, but I’m told hard trimming avoids them. Meanwhile, pray for a predator keen on cydalimas.