Summer springs eternal with the Garden Conservancy’s Open Days Program. The organization, which is dedicated to preserving exceptional American gardens for the public’s edification and enjoyment, hosts self-guided tours of privately maintained gardens from early spring through the fall; this month, three local spots open their gates to the masses. On the 8th, visit Eastward in Brewster, which showcases long borders that front horse paddocks; and Pawling’s Brine Garden, whose highlights include a naturalistic six-acre garden and arboretum. Rocky Hills, a Mount Kisco landscape that is open on Oct. 22, boasts a variety of unusual trees, including black walnut, stewartia, and magnolia. Admission to each garden is $5. Call 888-842-2442 or visit www.opendaysprogram.org for hours and directions.