It’s easy to think of brilliant artists who painted plants. There’s Van Gogh and his heady sunflowers, Georgia O’Keeffe and her spiraling petals, Claude Monet and his eternal water lilies. But what of artists whose works express ideas based on plant life? Isabella Stewart Gardner believed that horticulture was a “living art” and she made sure it was present in her museum. In this exhibition, site-specific installations by Cerith Wyn Evans, Piero Golia, Zheng Bo, and Ackroyd & Harvey populate the museum’s blooming courtyard. It’s the perfect summer show. —Elena Clavarino