Megan McCaslin, a former journalist, was introduced to the wonders of gardening by her father. As a child, she wandered with him among the oaks and camellias of their Los Angeles property, learning the Latin names of plants. She didn’t really dig in until, as a newlywed, she and her husband deemed themselves the New Orchardists, planting rare fruit trees and tending raised beds of flowers and vegetables in their Palo Alto garden.