Emma Townshend: British Gardens in Time - oh, BBC, what do you think you're doing?

The mother of all arguments is about to divide gardeners up and down the nation

Great Dixter remains a spectacle of exemplary horticulture and admirable structure (Rex Features)

I don't know whether the BBC was specifically trying to start a squabble, but last week it defo did so. Forget the very mild controversy over Benefit Street or that tiny bit of gossip you may have heard about Strictly's Susannah leaving her husband: this is the big one. Yep, if you want to get the nation really ranting, you know what you need to do? Kick off a row about the best gardens in Britain.

In particular, you need to commission a big series called British Gardens in Time, with nice presenters such as designer Chris Beardshaw and acclaimed garden historian Andrea Wulf; and then include only FOUR gardens. All of which are ENGLISH. And none of which is further north than junction 17 of the M6. (That's Crewe, for crying out loud.)

The series begins on BBC4 on Tuesday with Stowe, an elegant, huge and leg-knackering landscape very handily located for Silverstone race track. Stowe is also, once you start to look into the history, a singularly argumentative garden. Despite all the apparent Arcadian ease, Lord Cobham, the 18th-century landowner, created most of it during a period of political exile after falling out with Whig prime minister Robert Walpole.

Far from trying to distract himself from his worklife woes, Cobham went all out to make a garden that had a massive go at Walpole, with a "Temple of British Worthies" to hammer home the point about good and bad government. Seldom has a rolling landscape had so much bitter political venom put into it. And the result is superb.

If you like this kind of thing, you must get the series' accompanying book, written by distinguished garden historian Katie Campbell. Campbell treads a nice line between juicy facts and the aesthetic qualities of the gardens. I adore her description of Jane Austen-ish tourists turning up in carriages, buying guidebooks and filling up the local inns, while commendably tipping the head gardener.

The Beeb's most intriguing inclusion is Biddulph Grange, a Victorian garden near Stoke-on-Trent that sort of has to be seen to be believed. The garden's maker was James Bateman, son of a businessman father who'd been "unscrupulous but extremely successful", according to Campbell. Shadily accumulated cash funded an orchid habit that began before James had even finished university; and later, a properly crazy garden with a tomb-like Egyptian garden, scarlet Chinese bridge, and stupendously likeable, er, thing built entirely out of tree stumps (apparently they were all the rage in Victorian times).

The series winds up with two great English gardens. Nymans is in West Sussex, and I've never really fallen in love with it, though I understand it is technically possible to do so. Campbell calls it "the most exquisite Edwardian retreat of all", though here, my argumentative side starts to rear its head. Why not include Arts and Crafts Standen or tumbling-bordered Gravetye instead? (And that's just in Sussex.) If we are being completely obvious, where are Britain's most famous gardens internationally: Hidcote, Sissinghurst?

And if we're being more devolved in our thinking, where are the Edwardian gardens of Yorkshire, Derybshire or the Lake District? Bodnant, the Edwardian jewel of North Wales; Mount Stuart, on the Isle of Bute, just 90 minutes from Glasgow? I felt annoyed for all of these head gardeners, once more ignored.

But in the end, the series finishes exactly where I'd have picked myself: Great Dixter, for my money (£8.80 admission, if you were wondering) is the best garden on our island. Christopher Lloyd, its maker, and his admirable successor Fergus Garrett offer a changing spectacle of flowery loveliness in an underpinning structure of perfectly balanced weight. And for once, I'm brooking no argument.