Would you be so kind as to tell me when rhododendrons are usually at their peak bloom?
The peak season for Rhododendron blooms would probably be May, but there are Rhododendrons which bloom earlier and later than this as well (March through June). For more detail about which species bloom at what time, you may find this link to Oregon State University’s Landscape Plants web site of interest.
From the Washington Park Arboretum’s list of plants at their peak:
March: Camellia, flowering cherry, corylopsis, daphne, forsythia, heather, hellebore, magnolia, rhododendron, witch hazel.
April: Azalea, barberry, camellia, flowering cherry, halesia, maple, madrona, magnolia, rhododendron, serviceberry.
May: Crab apple, dogwood, magnolia, mountain ash, rhododendron, red bud, serviceberry.
June: Rock roses, brooms, Korean dogwood, rhododendron, stewartia, styrax