April has put on her party dress. Dogwoods, redbuds, cherries and crabapples are flouncing their fancy petals and the air is rich with heady perfumes of viburnums and lilacs. Some early blooming perennials are getting in on the act, and the freshly cut lawn adds a top-note of clover and new-mown hay. I find myself making excuses to weed near honey-scented spurge, growing by the front gate. Euphorbia cyparissias , with blue-green, ferny foliage and acid-yellow flowers is buzzing with bees and...