The great laurel, or rosebay, is considered one of the hardiest of the wild rhododendrons. Its natural habitat in the eastern parts of North America extend to New England, where winter conditions can be very like those in Finland. Some rhododendron enthusiasts consider this species questionable for garden use because of its straggly habit and late flowering, which is partly hidden by new growth. On the other hand, this is the only species which can be used in Finland to extend the flowering season into July. The flowers are pure white, with occasionally a touch of red or violet. On the upper petal there is yellow-green patterning.
In the wild, great laurel is at its best when it has some protection from wind in shadowed hollows or on mires. In the most suitable parts of its range it forms impenetrable thickets and grows rapidly, sometimes to large tree size. In Finland it reaches about 2 metres but spreads its branches wide, covering several square metres.
Recognition is easy, even on first sight. It has typical small leaves at the growing point, which distinguish it from the Mustila rhododendron (R. brachycarpum var. tigerstedtii), for example.