Spring is the peak season at Jenkins due in large part to an impressive collection of rhododendrons and azaleas. The Arboretum maintains a collection of nearly 5000 accessioned rhododendrons, azaleas and hybrids from around the world. There are also several natives including the rosebay rhododendron (R. maximum) and pinxter bloom, flame, and sweet azaleas (R. periclymenoides, R. calendulaceum, and R. arborescens respectively). The blooming season is long starting in late March with purple Rhododendron dauricum and pink Korean azalea (R. mucronulatum) and ending in late July with the red-orange plumleaf azalea (R. prunifolium).