Fresh from his award-winning monograph on penstemons, Robert Nold turns his attention to one of the best-loved - and most frequently misunderstood - groups of garden plants. "Columbines: Aquilegia, Paraquilegia, and Semiaquilegia" is the first gardener's guide to these striking plants in more than half a century; and in his funny, personal, and charming prose, Nold makes sense of the thorniest taxonomic and horticultural questions they present. Sixty-five...