The Bluebells are still looking lovely, so it's worth a visit while they last.

The American shrubs and trees and also flowering this month; look out for the Rhododendron maximum in the Chinese Bridge Peninsula.  This was the first Rhododendron introduced to England. 

Also look out for flowers beginning to bloom in the American Roots display, both in the theatre of plants and in the borders.  Here is the Bog laurel (Kalmia polifolia), under the John Bartram panel.