in Thoreau’s Journal:

Lady’s-slipper almost fully blossomed…. The shrub oaks are now blossoming. The scarlet tanagers are come. The oak leaves of all colors are just expanding, and are more beautiful than most flowers. The hickory buds are almost leaves. The landscape has a new life and light infused into it. The deciduous trees are springing, to countenance the pines, which are evergreen. It seems to take but one summer day to fetch the summer in. The turning-point between winter and summer is reached.  The birds are in full blast. There is a peculiar freshness about the landscape; you scent the fragrance of new leaves, of hickory and sassafras, etc. And to the eye the forest presents the tenderst green. The blooming of the apple trees is becoming general.