London has a really new garden. Queen Mary’s formal rose garden up near the zoo in the Regent’s Park is a stalwart classic, still looking immaculate in early autumn. Now, next door to it, is Queen Elizabeth’s, as different as two queens can be. Our late monarch is celebrated in a thoroughly modern, 21^st century way, with a swelling plateau largely of grasses, crouching or brandishing sheaves of all the colours related to corn. Wide paths wander through it; the main one of flecked concrete composed, we’re told, of demolished buildings on the site. Winding secondary paths have an annoying gritty surface.

Surveying it all from the top is a brick gazebo or lookout that was once a water tower. Behind it the roofs of some banal buildings, will soon be screened by newly planted trees. The rest of the garden is surrounded by the tall green wall of the Regent’s park.

In October the dominant colours are of the grasses, with here and there a brilliant pop of blue; under them we’re told are thousands of spring bulbs. I shall go in April, but meanwhile we have a thoroughly consistent and memorable example of modern planting to admire.

As I write an inch of rain would be more than welcome; whether it’s worth writing about is questionable. Yet weather is the cup all gardeners have to drink from. The years we spent living in Essex, planting trees and watching them shrivel away, left scars on my soul. It was why thirty years ago we bought woods in Snowdonia where you can count on 50 lovely inches a year.

High on my bookshelves, almost out of reach, is a set of one of Hortus’s predecessors: The Gardeners Magazine of 1829 – 1849. Our preoccupations have changed little. The most shocking change is the staff situation. We have fewer under-gardeners. In fact, I’m not sure when I last heard anyone say the word. The pity is not that the boss has to get his hands dirty; it’s that so few of the lower orders have the joy of rooting, cutting, pruning roses (or stoking boilers).

Wasn’t it a far smaller gardening world then? It seems not. The Gardeners Magazine has correspondents all over Europe and the Empire, and particularly keen ones in Australia, gardening upside down.

The volumes on my shelf end with 1843, which starts on page one with the notice ‘The Summary for the year 1843 is unavoidably postponed, on account of the Illness of the Conductor, who hopes he may be able to give it early in the year 1844’. London’s tireless energy, through constant arthritis and despite losing his right arm, produced not only his magazine, but his Encyclopaedia of Gardening, his Arboretum at Fructicetum Britannicum and multiple plans for landscape gardens, botanic gardens and London squares. With the help of his equally prolific wife Jane, he designed greenhouses and pioneered solar heating systems.

The blue plaque on the Loudons’ house, 3 Porchester Terrace in Bayswater, reads ‘John and Jane Loudon: their horticultural work gave new beauty to London Squares. It did far more than that. I was thrilled to discover that the street where I was born in St John’s Wood, Loudoun Road, was named after him (with a spelling mistake)

I’ve just come across my desk diary for 1976, a Country Gentlemen’s Association volume. Here we are in August ‘76, in the year that set new records for drought: “Staying at Derreen (in County Cork) climbed Curraghcreagh; a vertical bog” was one entry. Meanwhile, in 1976, the saplings of our future Saling Hall arboretum shrivelled and my arms grew longer carrying watering cans.

So we’re off to Ireland again.

If visiting nurseries and reading plant catalogues ever gives you that impression that the famous plant-hunters, Wilson and the rest, have got the world pretty well sewn up and there’s little else to discover, have a peep at the catalogue of Crug Farm Plants. Bleddyn and Sue Wynn Jones, from their Welsh pastures within sight of Iris Mon (Anglesey to you or me) have spent decades in remote parts of the world finding and recording hundreds of plants you probably never heard of. They’re still at it, and their website will make your mouth water.

Their ever-changing website tells the story. A large part of their stock of new introductions don’t even have names yet: they go by collection numbers. Some should even have warnings attached. One climber of theirs I planted shinned up and over our Welsh stone mine building in a single season, sneaking into every gap in the stones, so that we still haven’t entirely got rid of it five years later. Not that I’d put you off experimenting. St Christopher looks after travellers; who looks after gardeners?

The weather this year is making even the indifferent aware that nature can make life uncomfortable. Places that are almost bywords for pleasant living and delicious produce have gone up in smoke.

It has been agonising to watch fire racing through forests and laying waste to people’s homes and livings. There has long been a green lobby urging us to take care of our world. Generations ago it was christened Only One Earth. I was fortunate to know one of its principal protagonists in this country, Dame Barbara Ward, and will never forget a summer night that a few of us spent walking round Possingworth lake in Sussex. I was learning to feel a part of nature.

Of course, it’s much harder to feel in London. We appreciate our parks alright, but how much thought do Londoners give to the trees that shade us and the green spaces where we can rest our eyes and minds?

The Metropolitan Public Gardens Association was founded (by a forebear of my father’s friend Lord Brabazon) getting on for two hundred years ago. Its impossible to say how much less green it would be without what the MPGA has been able to do, but nobody can deny it’s been worth doing, its results are all arounds us, and they help to make London the wonderful place it is to live and work.

We are all here because we know this. We also know it’s our responsibility to keep planting, to nurture our green assets and to add to them. It’s not enough to be passive and sit under trees. Our children and their children need more. Let’s get planting.

You could say that my sister is keen on tomatoes – though ‘obsessed with’ is closer to the fact. They’ve had perfect growing conditions this month. Jack’s beanstalk gives the idea. I suggest pinching out some axial shoots and discouraging growth above the garden wall. “Hands off’, she tells me. ‘Don’t touch them’.

An Italian visitor turns up. ‘Your tomatoes are out of control’ he says and pinches out precisely what I was banned from pinching. A prophet is not without honour…..

The shingle at Keyhaven seems designed to discourage you from going in for a swim. All its edges are sharp. The water though is inviting; lazy wavelets from the calm strait between Hurst Castle and the Isle of Wight. Hurst Castle is the impressive guardian of the narrow western entrance of the Solent, a mere mile wide but a swim not advised when the Solent’s tricky tide is flooding by. But there is nothing like the traffic here that keeps the eastern approach by Portsmouth so busy.

Keyhaven remains a little fishing port, with seven or eight boats going out round the Needles, often, I’m told, to harvest cockles, of all things. The market for tons of cockles? Apparently Korea can’t get enough. The village has a good pub, The Gun Inn, and a huge car park. Hawker’s Cottage, near the pub, is where the extraordinary diarist, wildfowler and inventor Colonel Peter Hawker lived.

Hawker limped from a wound in the Crimean War, but before dawn in January he and his man would go out with their guns, wading through deep mud to slaughter incredible numbers of birds. He also regularly taught piano in Paris at the opera house by a new method of his own, travelling from Southampton to Cherbourg and by train via Rouen to Paris. He took his latest design of a breach-loading rifle to the Great Exhibition, standing in the opening queue every morning to demonstrate it; Prince Albert showed it to the War Office, which adopted it.  Do read his diaries.

Perhaps finishing schools have finally finished. I no longer circulate in the milieu of debs, their delights, coming out dances and girls being ‘finished’, ready for the Season, the husband-hunt. Does it still exist?

I ask because we have just been staying at Hartwell House, near Aylesbury, where it happens my sister Pauline, ten years older than me, was ‘finished’ before going on, not to marry a deb’s delight, but to travel the world, to work as a stewardess for BOAC and eventually to marry a brewer (whose brewery you pass in Chiswick on the way to the M4).

Hartwell House has lots of ‘previous’. In the aftermath of the Napoleonic wars it was leased to one of France’s last (and apparently its fattest) kings. Louis XVIII was, shall we say, picky about his food. His substantial staff at Hartwell included a predegustateur. I described his job in Trad in July 2015. Be assured no gritty pear or tough-skinned apple ever reached his majesty’s lips. The orchard where these perfect fruits were grown is still within the walls at Hartwell. By a miracle the vast scar of HS2, the folly railway, just misses the park before going on to devastate the Lee, the lovely estate of the Stewart-Liberty family.

Hartwell is, by what seems another miracle, in the care of Historic House Hotels, a work of extraordinary philanthropy that is preserving and putting to good use three important houses. The others are Middlethorpe Hall on York racecourse and Bodysgallen near Conwy in Snowdonia, or Eryri as we are now supposed to say. All three houses were bought, restored, furnished with antiques and given to the National Trust as a going concern (not without the pool and spa everyone expects these days). The Trust can run a hotel as well as any country house. Indeed their standards are so high that you could still believe the old regime was still going strong. Talk to the swan permanently stationed by the front door, or the cattle or the sheep that nosey up for a chat. Or the carp that formation-swim under the stone bridge. Hartwell seems to exist in an older world.