What is the common name for Cotinus coggygria 'Royal Purple'?

Cotinus coggygria 'Royal Purple' is commonly known as the Royal Purple Smoke Tree. This plant is recognized for its striking purple foliage and unique smoky, fluffy flower clusters that resemble puffs of smoke, especially when backlit by sunlight. Its vibrant color makes it a popular choice in ornamental landscapes, and it typically grows as a small to medium-sized deciduous shrub or small tree.

The other options do not accurately describe Cotinus coggygria 'Royal Purple'. Rockspray Cotoneaster refers to a different genus and is known for its spreading habit and berries. The Crimson Pygmy Barberry is a specific cultivar of Berberis that features compact growth and bright red foliage, distinct from the smoke tree. Winterhazel is another unrelated plant known for its winter-blooming yellow flowers. Therefore, the designation of Cotinus coggygria 'Royal Purple' as Royal Purple Smoke Tree aligns correctly with its characteristics and is widely accepted in horticultural contexts.