These gardens are a short taxi ride out of Georgetown or they are at the bottom of Penang Hill if you descend by road. They are free to enter and have many lovely trees and flowers. There is a train (paid) that will carry you round the gardens if the heat is too much for walking; it does get very hot in the afternoons. For me, the highlight of the gardens was the Dusky Leaf Monkeys eating the topiary trees near the entrance. They are beautiful and seem quite at ease around people. They are also less cheeky and noisome then the Macaques up the hill, near the top of the park.
Worth the trip for the Dusky Leaf Monkeys alone.