No preregistration is required for these monthly classes at the Botanical Gardens. Classes are from 9:30 a.m. to noon, unless otherwise indicated; $16, $8 for members, includes admission to tour the gardens. "Gardening for the Newcomer" is the first Saturday. "Xeriscape Not Zeroscape" is the second Saturday. "Successful Plants for Tucson Gardens" is the third Saturday. "Rainwater-Harvesting Workshop" is the fourth Saturday. The gardens frequently offer classes on a wide range of gardening and related topics, including photography, painting and fauna that frequent Tucson gardens; fees vary, but include admission to tour the gardens. Call or visit tucsonbotanical.org for more information.