There’s nothing more satisfying to a gardener than growing plants from seeds. From annuals and perennials to trees and shrubs, success can be achieved if you understand what triggers germination. On Saturday, April 6, from 9 – 1 at the Dana Greenhouse Classroom at the Arnold Arboretum, expert propagator Jack Alexander will share techniques for starting various types of plants— annuals (including vegetables), trees, and shrubs— from seeds. This workshop is for beginners and those who have been frustrated in past attempts to transform seed to seedling. Students will leave class with a selection of seeds raring to grow. Aftercare will be necessary. $50 for Arboretum members, $65 for non members. Register on line at www.arboretum.harvard.edu.  Photo from www.growingagreenerworld.com.