|Sweetpea 'Cupani': the original, introduced in the 17th century|
It was brought home to me when I went round the inspirational kitchen garden at Knightshayes recently. It's no showcase museum piece but a belt-and-braces, workaday sort of garden which pays its way by selling its produce, so what it grows needs to be worth growing.
Its indefatigable head gardener Lorraine is a keen advocate of heritage varieties – 104 heritage tomato varieties (she likes German beefsteaks and the near-wild species tomato, Solanum pimpinellifolium) and 10 heritage garlic, plus peas, sweetpeas and potatoes.
|Pea 'Magnum Bonum': modern pea breeding has focussed on dwarf, self-supporting peas but hugely tall 19th century varieties like this one and the 'Telephone' strain are far heavier yielding and more satisfying to grow all round|
|Achocha in the greenhouse: this one is the exploding cucumber type (Cyclanthera explodens) not the edible achocha which is a finer, less coarse (if also less amusing) plant. The fruits of the edible one taste of sweet peppers|
Well, as a set of criteria for choosing something worth growing in your back garden I can't think of a worse lot of reasons.
You may have noticed that there are a few things missing from the list. What about flavour? Juiciness? Explode-in-the-mouth ripeness that makes you dance round the kitchen in glee?
|Babington leeks and and old Italian variety of green garlic, in the main garden|
It's telling that at the Edible Gardening Show earlier this year, when Suttons brought a few Danish trolleys' worth of the weirdest edibles they could think of as an experiment, they'd sold out by lunchtime on the first day. This is no passing fad: our curiosity is well and truly piqued.
And then there are all the ornamentals which turn out to be edible: Fuchsia berries (try 'Riccatonii'), flowers from sweet rocket to nasturtiums and violets, Eleagnus berries and elderflowers.
|Heritage toms in the lean-to greenhouse. Lorraine says they go through a 'teenage' stage and sulk for a while when they reach about 6" tall: but they get over it, and romp away so fast they catch up with everything else around|
Some argue heritage varieties aren't worth growing; well, I'll continue to swoon at the faint-inducingly gorgeous flavour of my 'Marmande' beefsteak tomatoes, if that's OK with you. Tricky as hell to grow, but you keep going just to have one unforgettable taste – and you try buying that in the shops.
And besides, heritage varieties saved by The Heritage Seed Library preserve our genetic pool of veg varieties – whether or not they're worth giving garden room to - so we don't narrow it all down so much we're breeding in ever-diminishing circles.
At the other end of the spectrum you've got the early adopters: those who say traditional veg are boring and everyone should be throwing out their spuds in favour of yacon. Well: given that all my potatoes have gone over to blight in the last week there might be something in that (though I'll mourn the loss of my 'Duke of York' should that sad day ever come).
But on the whole, for most people (certainly for me) the whole process of getting to know exotics is a series of experiments. I've tried and rejected tomatilloes – lovely plant, but not enough crop or uses for it (much as I like salsa) to justify the greenhouse room. But I now grow sweet potatoes every year, in big baskets under cover, as though the crop isn't huge it's big enough and it makes a nice change from the spuds.
And just as we thought there was time to get bored, along come yard-long beans, Chinese arrowroot and lablab beans courtesy of Sally Cunningham's Sowing New Seeds project for Garden Organic. Some will go the way of ra-ra skirts and beehive hairdos: others (my money's on the lab-labs) will be the allotment staples of tomorrow. Isn't it great?