Theer are two really exciting movements in gardening at the moment. The first I have dubbed ‘the Sheffield School’: a group of plantsmen working out of Sheffield University, who are developing naturalistic meadow-planting techniques (they’ll soon start planting up the new Olympic park in East London).

The second, and just about its polar opposite, is Garden Conceptualism. This is an approach to garden design that’s predicated on ideas as opposed to horticulture or modern architectural styling (in other words, it ignores the traditions in which most garden and landscape designers have been trained during the past half century). It’s an attitude to design that sometimes results in highly artificial-looking gardens, where plants take second place. Instead, a range of explicit meanings are woven through a space which can then be ‘read’ as a narrative or through its symbolism.

An example is Martha Schwartz’s design for Grand Canal Square in Dublin’s regenerated docklands, which takes glamour as its conceptual theme. Dr Schwartz has introduced a sense of the bustle of the catwalk by means of two strident red ‘carpets’ of pavers bisecting the plaza, the carpets ‘peopled’ by a couple of dozen 50ft- high red poles, resembling outsize lipsticks, which glow at night. The Conceptualist approach is not for the shrinking violets of the garden world.

If this trend sounds a little tiresome to the many romantic British garden-lovers who simply adore immersing themselves in seas of shrub roses at this time of year, or who delight in pondering obsessively over such esoteric delights as epimedium foliage, then think again. It turns out that Garden Conceptualism, although not perhaps everyone’s idea of the sort of garden one might actually like to own and tend, can nevertheless provide an entertaining day out. The typical Conceptual garden show (they occur in Portugal, Sweden, France, Germany, Canada and the USA) lies halfway between a flower show and an exhibition of installation art.

Last month saw the launch of the most ambitious Conceptual garden show yet in Britain: Future Gardens, a stirring entrepreneurial venture set on a chalky, open site near St Albans in Hertfordshire, just next door to the Royal National Gardens of the Rose (providing potential for a double visit, if one has the energy). Thirteen exciting show gardens, in situ for four months, have been constructed along the general theme of conservation and sustainability (whatever that is). But don’t let the ecological correctness put you off there are some really super gardens to discover here.

Among the most innovative ideas at Future Gardens is a jungle of artfully tangled branches that define Michelle Wake and Chloe Leaper’s Release Garden, apparently inspired by Wagner in that the garden ‘follows a pattern often found in classical music: a symphonic build-up, then a sense of release followed by a point of calm’ (you can get away with that sort of thing in the Conceptual sphere). It was more like a garden scaled version of an Andy Goldsworthy sculpture.

One of my favourite gardens is Marcus Green’s For Cosmo, Cosmo being the designer’s dog, a Bracco Italiano, with whom he loves striding the Northamptonshire hills, the real inspiration for this garden of long native British grasses.

Many native British grasses and wildflowers are on show at Future Gardens they can even be found on horticultural artist Tony Heywood’s remarkable Anthroscape 3 structure. And they are there in a garden designed by Andy Sturgeon, a familiar name who was absent from Chelsea this year. Future Gardens is just the opening salvo of a two-phased operation.

The main event, in financial terms at least, is Butterfly World, a huge geodesic dome filled with 10,000 tropical butterflies, scheduled to open in 2012, funds permitting. If Butterfly World looks anything like the plans when it’s finally built, it will be a smaller-scale Eden Project within easy striking distance of London, the second half of a real double whammy of a visit.

For details of the Future Gardens show, which is open daily until October 4, telephone 01727 869203 or visit www.futuregardens.org

* For more gardening like this every week, subscribe and save