Spring is when I appreciate perennials most. Looking out over the garden, all I can think of (well, maybe not all) is how much work lies ahead. This year may not be so bad. The garden was mulched last fall. The compost was spread around. Some leaves remain on the ground to give winter protection; others have been raked or composted. But every year, when I see the perennials - like these hostas greening up, I feel relief and happiness. Perennials are a beautiful invention. They return faithfully every year, spreading as far as we let them and, once divided, giving us free plants to share or plant. Hostas are among the most reliable, and while some still think of them as those boring green and white varieties that were (and to some extent, still are) planted by the thousands years ago, there are more exciting ones entering the marketplace every year. I've become a fan. I love my creamy 'Guacamole' and my incredibly substantial 'Sum and Substance,' which looks more like a flying carpet every year. Hostas come with fragrant flowers, upright vase shapes, slivers for leaves and all shades of blue and green, yellow and white. Yesterday, a caller from Chester County said he'd removed more than 100 hostas because the deer were feasting on them - ah, now you've discovered their down side - and replaced them with ornamental grasses. Could he divide the grasses now or wait? Whatever. If you do it too early and the worst happens - they freeze or die - you just divide another clump. Annuals surely give us longstanding color and brightness and that's a big gift. But perennials are a great deal. They're a onetime investment that pays off year after year. They're in it for the long haul, which - these days, especially - has a certain appeal.