THE PERENNIAL GARDENER by Frederick McGourty Boston: Houghton Mifflin 250 pp., $24.95 FASHIONS are anything but halfhearted in America. ``We jump in with zest, whether it is dieting or finding the perfect ice cream,'' according to Frederick McGourty. And while that might be perfectly acceptable in many fields, it isn't in the garden.
``During the current fascination with perennials,'' McGourty says, ``a lot of gardeners may be unwittingly digging graves for their enthusiasm'' in deciding on both the site and size of their perennial beds. It's not that he is against such borders - he has almost 20 of them at his Hillside Gardens nursery in northwestern Connecticut. But half his work as a garden designer involves correcting flaws of placement, shape, and size in existing borders - trying to ``salvage the dream,'' as he puts it. Hence his book, ``The Perennial Gardener,'' designed, you might say, to keep the dream alive.
That most brilliant of English gardeners, Gertrude Jekyll (1843-1932), designed perennial borders on the grandest scale. She has won McGourty's admiration, but, he points out, Jekyll ``had her heyday at the height of the British Empire, when there was plenty of loose change around for the right people to have the right gardens.'' In those days, ``gardeners, some very good ones, could be hired for a modest sum to care for such places.'' In the United States today, money may not be the limiting factor, but there is an acute ``shortage of skilled gardeners to care for these potential Hindenburgs.''
On the other hand, McGourty's message is one of hope: With a little practice, anyone can develop the skills to build and maintain more modest perennial gardens to delight homeowner and visitor alike. While his book is filled with sound technical advice, it also makes for pleasant reading. Take for instance McGourty's problems with deer in the extensive hosta plantings:
``A few years ago one fawn regularly bedded down in a large grouping of H. `Frances Williams' and had to be shooed away periodically like a neighbor's dog. She stopped every twenty feet, looking over her shoulder with a doleful expression to see whether I really meant it. I did - `Frances Williams' is a ten-dollar hosta and she could at least have had the consideration to sleep in the lancifolias, at four dollars a plant.'' Of his introduction to pesto, ``that ethereal sauce'' combining fresh basil leaves and garlic, he says: ``In those days, garlic wasn't often used west of the Hudson River, except in bad jokes,'' and ``the only basil known to Maine Street Americans had the last name of Rathbone.''
While the book's title refers, quite accurately, to the copious information about perennials packed between its covers, it might also refer to a mind-set: the perennial gardener.