From the Website:
The beauty of the Azalea Garden changes and evolves throughout the year. A flowering cherry tree heralds the start of the season in mid-May, followed by azaleas and rhododendrons in many hues in late May through June. July blooms include Japanese iris, smoke bush, rosebay rhododendron, and the fragrant sweet azalea. August is quiet and serene, accented by blooming water lilies, and in September and October the garden glows with the colors of fall.
Rhododendrons and azaleas are planted throughout the garden, and many are native to the mountainous regions of the world. The Pink Shell Azalea, Rhododendron vaseyi, is native to the Blue Ridge Mountains of North Carolina and provides much of the garden’s structure. It grows alongside Rhododendron kiusianum from the mountains of Japan and Rhododendron canadense, Maine’s own native azalea.