Colleen Plimpton is one of those fortunate people who is smart enough to learn from all the people - and sometimes the animals - who come into her life. In her charming, conversational book, Mentors in the Garden of Life, she tells us about relatives like Aunt Louise and friends like Kathleen, and expert gardeners like Sydney Eddison who have been important to her in life, and in her garden. Each vignette that captures a personality and time ends…