North of Tarrytown [1] and a few miles northeast of Ossining, peaceful 650-acre Teatown Lake Reservation (1600 Spring Valley Rd., off Rte. 9, 914/762-2912, www.teatown.org [2], dawn–dusk daily) holds a shimmering blue lake, hiking trails, an interpretive museum in two Colonial buildings (9 a.m.–5 p.m. Tues.–Sun., year-round, free parking and admission), and wildflowers galore in the spring, summer, and fall.
Most of the 200 species of flowers grow on an isolated two-acre island in the middle of the park, accessible only by tour ($6 per person, reservations required, children under 14 not permitted on island).
Links:
[1] http://www.moon.com/destinations/new-york-state/the-hudson-valley/lower-hudson-valley/tarrytown-and-sleepy-hollow
[2] http://www.teatown.org