Hydrangea quercifolia 'Ruby Slippers'
Compact oakleaf with cone blooms that open white and age to deep ruby red. Burgundy fall foliage finishes the show.
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.