Future now: Landscape design has reached new frontiers

Here's something to relieve the tedium of the M25: see if you can spot a 26ft-high terracotta pot near junction 2(12A). The pot, together with an equally large hand fork, is a new landmark to fanfare Butterfly World near St Albans, Hertfordshire. It is currently in Phase I of its £27m development, but already open to visitors. The giant props will eventually be dwarfed by a large, glass dome that will house an incredible 10,000 butterflies and become the biggest butterfly walk-through exhibition in the world. Until then, the landscape and gardens in the 27-acre site will provide the main attraction, as they re-establish wildlife habitats that have suffered from development.

The masterplan for the grounds around this impressive conservation project include one of the most spectacular road-side wildflower displays, to welcome visitors, and a number of smaller butterfly-themed gardens to capture the imagination of both children and adults. Designed by surrealist Ivan Hicks, the gardens – such as "Theatre of Insects" where gabions are filled with discarded, man-made objects in which insects often reside – provide an eccentric but fun-filled take on bio-diversity and ecology, while allowing visitors an insect's-eye view of the giant dome's progress.

Butterfly World is also host to Future Gardens. Formally known as The Festival of the Garden at Westonbirt, it has re-emerged (metamorphosed if you like) to showcase the cream of conceptual gardening from both UK and international garden designers. Twelve gardens, selected from over 100 entries, are on display this year (until 4 October), allowing visitors to see how gardens change over time.

Conceptual gardens (a term coined by garden critic Tim Richardson) champion lateral thinking and freedom of expression, often ignoring the practicality of the "real" gardens we see at shows. Richardson, in his book on the subject Avant Gardeners, sees it as "... the harnessing of an idea, or a set of related ideas, as the starting point for work that was characterised by the use of colour, artificial materials and witty commentary on a site's history and culture."

Like them or not, they are becoming increasingly popular with designers looking to break away from convention.

The 12 gardens all carry an ecological theme but differ widely in their interpretations; they range from a simple dog-walking garden ("For Cosmo" by Marcus Green) to a butterfly-inspired field ("Metamorphosis" by Peter Thomas), each one sponsored to the tune of £25,000. This is a fraction of what a garden costs to build at the Chelsea Flower Show and one might expect a serious shortfall in terms of quality. This isn't the case. The standard is better than ever and one or two gardens would look more than comfortable as a permanent feature at Butterfly World.

Paul Dracott's "Exoskeleton" is hot and vibrant with late summer perennials, while Jane Hudson and Erik de Maeijer's planting in "Nest", which uses coppiced willow to express a powerful message of "nurture", looks like it's already in its second season. Watching these plants mature and how they resonate with light and the elements of this windy site is all part of the pleasure – particularly as these two gardens rely on the site's exposed nature to add an extra dimension of movement.

Andy Sturgeon's "Urban Greening" consists of wheat planted in bold blocks which roll with each breath of wind. Rusty steel panels cast an almost watchful presence in this garden, which addresses the loss of green space in our cities and how good-quality landscaping can improve the environment. The "Welcome" garden by Rosita Castro Dominguez et al is one of the more dynamic concepts, with kite forms dancing on a breeze among nectar-rich lavender, scabious and verbena. The view, mainly from within a large metal cage, creates an interesting tension, questioning our relationship with nature and how we (mankind) are upsetting the balance.

The horti-élite might cringe at the thought of orange and white combined, but the effect is stunning in Bruno Marmoli's "The H Garden". A decked path cutting through a spangle of marigolds, gaura and nicotiana tempts you to explore what lies within the large orange polystyrene enclosure at the end. Within lie three white trees made of board, emerging from a black coal mulch. The atmosphere of this animated shrine is accentuated by a haunting soundtrack and the cloying musk of cleomes; it seems to explore our relationship with nature from both sacred and secular points of view (steel skulls add a pagan touch at the rear of the space).

Tony Heywood's "Anthroscope 3", a personal voyage into a surreal dreamscape, juxtaposes materials as obscure and intriguing as cattle horns, fleece, coal and jewellery. The amorphous island, Heywood's unique brand of geological language, is spawned and abstracted from the artist's personal reminiscences, engaging visitors who, whether they like it or not, will linger long.

More chaos greets you at the entrance to Michelle Wake's "Release Garden" where a redoubt of tree branches can only be accessed through a winding path. The confined journey eventually "releases" you into an area where herbaceous planting brings colour (and food for insects) among a copse of Salix babylonica 'Tortuosa' (twisted willow). A pool with a sculpture by Chloe Leaper provides a tranquil space at the end of the journey. Inspired by Wagner, the designer explores how gardens, like music, might affect people both physically and emotionally. Of all the gardens this has perhaps achieved the most in terms of giving a powerful sense of place.

The sculptor Fiona Heron is no stranger to conceptual design and her garden "Nature's Artistry – Autumn's Edge" is carefully orchestrated into her trademark segments of ordered space. Exploring "the sense of becoming and regeneration in autumn", the garden has an intriguing mixture of textures – with mulches of vegetation, chestnut hulms, pine needles and walnuts all chosen for their natural form and their pre-disposition to weathering and decay. The fragility and richness of nature's cycle is further accentuated by Heron's own sculptures – steel rods topped with a mix of eye-catching textures, glass, ceramics, card etc, all imitating nearby bulrush beds. A mesmerising experience.

Overall there are some extremely strong messages at Future Gardens – about our relationship with the landscape and how we interact with it throughout the seasons. If Butterfly World is looking to become a standard-bearer for the future of our gardens, it's certainly off to a flying start.

Visit futuregardens.org or call 01727 869203 for further information