Hydrangea paniculata 'Limelight'
Cone-shaped blooms open chartreuse, mature to white, then blush pink in fall. Tough as nails.
The leaves and flower buds contain a cyanide compound. It is rarely a problem for people, but it is listed as toxic to dogs, cats, and horses, so keep prunings away from animals that browse.
For gardeners who like to stay ahead.