Philadelphia area hosts spring garden festival Gardens Collaborative, a group representing 26 public gardens and historical homes, is coordinating the festivities. March 27, 2001 Share 1 -- green thumb festival is being held this spring in the Philadelphia region. Throughout May, the city and its environs will play host to this event, billed as the "world's largest garden party." Gardens Collaborative, a group representing 26 public gardens and historical homes, is coordinating the festivities.In Philadelphia, members include Historic Bartram's Garden, the Japanese House and Garden, Morris Arboretum of the University of Pennsylvania, Awbury Arboretum and Wyck.Other area gardens include Bowman's Hill Wildflower Preserve in New Hope, Scott Arboretum of Swarthmore College in Swarthmore and Longwood Gardens in Kennett Square, Pa., and the Camden Children's Garden in Camden, N.J.The group will work with operators to develop private tours and arrange lunches, according to Gardens Collaborative project director Barbara Klaczynska.Events are designed to appeal to a diverse audience, including children.The Spring Blossom Festival is set for May 20 at Tyler Arboretum in Media, Pa., with live music, games and crafts for kids, tours and a gardening workshop.On tap for May 19 is Children's Day at Japanese House and Garden.A martial arts demonstration, traditional music and dance,a Hira Doll display and tours of the house and garden are highlights.Footprints in the Gardens takes place May 5 and 6 and May 12 and 13 at Historic Bartram's Garden with a dance routine performed by teen-agers from north Philadelphia's Art Sanctuary.For additional information, contact Gardens Collaborative at (215) 247-5777, Ext. 207.