Having weathered a winter of drought and bitter frost, the UC Davis arboretum is bursting with brilliant spring blossosoms. Lavender and purple wild lilac bushes are set off by the vibrant yellow blossoms of the flannel bush. Other native California plants now in bloom are the wild rose, poppy and lupine. Now in its 56th year, the arboretum is one of the richest living museums in Northern California. Its 120 acres include more than 2,000 varieties of trees and plants, representing landscapes from around the world. This year, home gardeners might be particularly interested in getting ideas from the arboretum's Storer Garden, with its drought-tolerant perennials. The arboretum is open to the public, and guided tours are offered to specific areas each Sunday.