Hosta 'Halcyon' Halcyon' is one of the best blue-leaved hostas. It has medium, glaucous blue leaves that are lance-shaped when young, becoming to heart-shaped when mature. For the most intense shade of blue, grow plants in shade. In summer, the foliage is complemented by the bell-shaped, greyish-lavender flowers. The Royal Horticultural Society has given it its prestigious Award of Garden Merit (AGM) which is for plants of outstanding excellence.