Acer ginnala, May 10 Acer negundo, April 17 Acer platanoides, April 24 Aesculus glabra, May 8 Androsace occidentalis, April 24 Antennaria campestris, April 23 Aquilegia latiuscula, May 10 Asimina triloba, April 29 Asparagus officinalis shoots, April 24 Baptisia minor, May 15 Baptisia leucophaea, May 15 Berberis thunbergii, May 3 Berberis vulgaris, May 11 Callirhoe involucrata, May 26 Corydalis micrantha, April 23 Catalpa speciosa, June 4 Celtis occidentalis, May 8 Chaenomeles lagenaria, April 15 Convallaria majalis, May 10 Crataegus sp., May 11 Elaeagnus angustifolia, May 27 Hordeum pusillum, May 18 Iris vermanica, May 15 Iris pumila, April 20 Juglans nigra, May 13 Lappula echinata, May 27 Lepidium densiflorum, May 22 Medicago sativa, May 27 Mirabilis nyctaginea, May 26 Opuntia megarhiza, June 5