Registration is open for National Public Gardens Day, which will be noted locally by Bridge Gardens Trust, as well as the Madoo Conservancy in Sagaponack and LongHouse Reserve in East Hampton, on Friday, May 8. Free, one-hour guided tours will be given, beginning at LongHouse at 10:30 a.m., to be followed by a tour at Madoo at 1 p.m. and one at Bridge Gardens at 3.