American gardeners are familiar with the legendary scent of the common lilac ( Syringa vulgaris). But other members of the lilac clan, including most of the Asian relations and their hybrids, have luscious fragrances and other attributes that make them worth seeking out.

When hybridizers noticed that broadleaf lilac ( S. oblata), a Chinese species, flowered a week or two earlier than common lilac, they crossed the two and came up with a series of beautiful, early-flowering hybrids called S. hyacinthiflora. All have classic lilac fragrance. The plants, which can be grown in Sunset climate zones 1-7, may reach 15 feet tall with an equal width.

Many S. hyacinthiflora hybrids rank among the best lilacs in their color classes. These include blue-white 'Blanche Sweet'; bluish pink 'Excel'; light lavender 'Assessippi'; pink 'Annabel', 'California Rose', and 'Esther Staley'; purple 'Glory'; violet-purple 'Pocahontas'; and white 'Mount Baker'. Some of these, such as 'Annabel' and 'Excel', are very early bloomers that react to unseasonably cold temperatures by delaying flowers until the weather becomes milder.

Order bare-root plants to set out now or plant container-grown stock later. For a good selection by mail, check out Heard Gardens (5355 Merle Hay Rd., Johnston, IA 50131; 515/276-4533; catalog $2) or Select Plus International Nursery (1510 Pine Rd., Mascouche, Quebec, Canada J7L 2M4; 450/477-3797; catalog $1).