IS scent an "optional extra" in the garden? Stephen Lacey thinks it too often is but argues that it could effectively be a more integral part of planning, planting, and enjoying something that is still basically visual. "The aim," he observes in "Scent in Your Garden,should be to have a garden that entertains the nose at every turn on every day of the year." No season lacks scented plants, even if it is the foliage rather than the flower at some times that bewitches or assaults your olfactory sensitivity.
Lacey touches intriguingly on the "vague relationship" between color and scent: As a general rule, the less pigment the more scent. But - and this is the main body of his stimulating and useful book - his extensive and descriptive list of scented plants frequently includes plants with intensely strong color in their flowers that also pervade a warm summer evening with perfumes elusive or potent.
Some plants with wonderful scent are less than attractive (depending of course on individual taste). The shrub Mahonia aquifolium, which wows the nostrils early in the spring, is a spiky, dreary, green thing with congested yellow flowers, which I would have thought an unwelcome space-taker except for its scent. So clearly it should be in some obscure corner. On the other hand, plants with scent in winter really ought to be as near the front door as possible to be enjoyed. A paradox.
Lacey has much to say about siting scented plants for maximum relish, most of it good sense. However, his idea that small, scented spring bulbs, often endowed with marvelous but intimate scent, should be grown in beds raised high enough to be near the nose, does seem a little over the top.
But it would be impossible to read this highly informative book (illustrated by Andrew Lawson's consummate photographs, so rich and heady that you could almost imagine they exude perfume) without gaining an entirely fresh awareness of just how many garden plants are scented, and how relatively little we appreciate them.
Roses are of course, par excellence, scent flowers - and sweet peas, philadelphus, hyacinths, and sweet williams. But superlative fragrance also issues from certain kinds of rhododendron and magnolia - not to mention certain primulas, crocuses, wild cyclamen, clematis, and waterlilies and ... and ....
One plant much worshipped by gardeners that apparently never gives out the slightest perfume is the gentian. But this delightful genus includes plants with visual virtues so seductive that most of them are now, by necessity, legally protected in the wild. It's their rare blue color - ranging across just about every variation of that hue imaginable - that amazes.
Fritz Kohlein begins his book "Gentians" with a chapter called "Encounters with Blue Flowers" that captures more than anything else in his authoritative study the fascination of gentians.
The genus Gentiana (now separated by botanists from "Gentianella," which has become a separate genus) Kohlein reckons amounts to about 200 different species (not all blue-flowered). They come from Asia, the northern temperate zone, and the Andes. They often grow extremely high up mountainsides.
Not all gentians can be successfully cultivated in gardens, but Kohlein's list offers helpful advice on any that can. Anyone who already happily grows some of the more usual types - acaulis, verna, sino-ornata (which have been extensively hybridized for gardeners) - may well be tempted by this book to try some lesser-known gentians. G. cachemirica, for instance, from the Himalayas, is described as "a good garden plant ... at home in a sunny position in the joints of a dry stone wall." It is one of the t y
pes illustrated; the book's photographs are excellent. Words rarely convey the subtle but all-important difference between one plant and another.
Advice on soil, siting, propagation - even warnings about nurserymen who wrongly name particular gentians - are all sound, making this book a helpful reference. Kohlein suggests not growing the true species "acaulis" because available garden hybrids are easier. But he does acknowledge that even in ideal circumstances this gentian is reluctant to overwhelm the gardener with very many of its strong blue trumpets. He does not, however, suggest walking on it as an encouragement to flower more - advice one s k
illful alpine gardener once gave me. I'm not sure that it works, though it doesn't seem to do the plant much harm. Presumably it is quite used to the hooves of alpine cattle.