After a spring of wretched downpours and cold, cloudy weather, summer has finally begun -- at least unofficially -- and the bullfrogs are singing its praise.I slide my kayak into the lake at Tuckahoe State Park on Maryland’s Eastern Shore. It’s a sunny, breezy afternoon, and the lake is fringed by swaying reeds and the arrow-shaped leaves of water plants -- called Tuckahoe – whose roots were an important source of food for Native Americans.