Want to know what goes on in the Polly Hill Arboretum greenhouse and nursery? Hereâ€™s your chance to get more than just the tantalizing glimpse most visitors experience. Led by collections and grounds manager Tom Clark, weâ€™ll stroll right past the â€œEmployees Onlyâ€ sign and explore the inner workings of the Arboretumâ€™s plant production facilities. Weâ€™ll look at the nuts and bolts, hear about the impact these new facilities have had on the development of the Arboretumâ€™s living collection, and see some of the results of PHAâ€™s plant exploration trips to Japan and the Southeast, and local collecting here on the Vineyard. The excursion takes place Thursday, July 19, beginning at 10 in the morning in West Tisbury. $5/free for PHA members. For more information, visit www.pollyhillarboretum.org.