Flower power and mating

Sitting in a packed, warm auditorium for an entire day is difficult for outdoor types like garden designers and landscape architects. But there were few complaints at the annual seminar of the Garden and Landscape Designers Association a fortnight ago in UCD. This year's session featured three international speakers: Cornelia Hahn Oberlander from Canada, Alain Provost from France and Charles Jencks from the UK. Ireland's Angela Jupe, the founding chairman of the GLDA, gave the final address. The conference's theme was "Dynamic Styles for Future Gardens", but it was the efforts of an "early landscape architect", as described by speaker Charles Jencks, that sent a ripple of pleasure through the 250-strong audience. He was referring to the male bowerbird, a native of the southern hemisphere, who builds an elaborate figure-of-eight construction, lined with soft, black moss and decorated with iridescent blue beetles and yellow flowers.

The ornate open-air structure is designed to attract a mate, and proves that "the earliest reason for building a garden was to get the woman," said Mr Jencks. (He failed to point out, however, that the bower is an impractical bit of showmanship, and that the female, unaided by her suitor, has to fabricate a proper, functional nest a short distance away in which to hatch the family.)

Ripples and waves, of a cosmic nature, preoccupy Charles Jencks, a post-modern thinker of serious stature. His Garden of Cosmic Speculation on his property in the Scottish Borders represents "the universe writ small" and reflects some recent theories of the cosmos. The garden features stunningly sinuous land-shapes, lakes and sculptures symbolising soliton waves, DNA spirals, fractal geometry and black holes.

"Black holes bend light rays, and they compress time and stretch space", he related as he showed slides of his Black Hole Platform, a dizzying, swooping surface of aluminium and astroturf "squares" compressed, stretched and folded. The platform has a practical use as well as a symbolic one: a space for eating al fresco in summer. "Nothing grows in a straight line in the universe", was Mr Jencks's parting shot to a sometimes bemused, sometimes argumentative audience.

Geometry - straight lines and otherwise - also concerns Alain Provost, the French landscape architect who has designed a number of city parks, including Paris's Parc Andre Citroen. Because urban sites are neither rural nor pastoral, he says, "we cannot just produce simply pretty picturesque scenes". The best and most contemporary approach is "to put the emphasis on a geometrical element." His designs, therefore, show the space being divided up again and again into a series of gardens. One such park, partitioned into six themed gardens, has a place for everyone including a garden for "the old women", one for children, and another, "the secretary garden", which mimics a giant typewriter with squarely clipped shrubs as the keyboard and robinia trees trained into lollipops representing the metal keys.

Mr Provost caused a wave of envy when he stated that 50 hectares of parks had opened up in Paris over the past 20 years. A further surge of yearning was felt when he spoke of his budgets: in the millions, both in French francs and in English pounds. Cornelia Hahn Oberlander is also used to working on a grand scale, and for this type of project, she advocated strongly the use of mass-planting - where plants of just a few varieties are used in great swathes. Her design for a naturalistic forest garden, where "rhododendrons fall out of the forest in spring" and where the grass is filled with daisies in the summer, showed the effectiveness of this simple, bold system. But rhododendrons were not always so obliging for this renowned designer, as could be seen in a colour-clashing garden where "the client wanted pink and red rhododendrons and azaleas. So what can you do?" she shrugged. "You plant them!"

Ms Oberlander is a firm believer in ecological responsibility, and, where possible, uses grasses like sheep's fescue which needs mowing just once a year, and Poaalpina which never needs mowing. At the end of the afternoon, it was Angela Jupe's turn to give the conference the Irish perspective. Her lecture ranged from the vegetation of Star Trek planets to the unsuitability of prim Leyland cypress for the slightly disordered Irish personality. She advised people not to close themselves off from the landscape, but to "bring it into the garden. You own the landscape," she urged.