I went to the NYBGfor the roses but I got chrysanthemums, kiku, too. This is the third and final year for this extraordinary exhibit of Japanese chrysanthemum art forms set up at the Enid Haupt Conservatory courtyards. I was familiar with this form, Kengai, because similar cascades are created for our local Smith College Chrysanthemum show. All season long a single chrysanthemum plant is trained through wire mesh, pinched and artfully pinched again to create this waterfall of bloom.…