Cactus and Succulent Society of Hawaii: Annual moonlight walk and potluck dinner, 6 p.m. tomorrow, Koko Crater Botanical Garden. Palm specialist Ray Baker of Lyon Arboretum will speak. Free. Bring a flashlight. Call 522-7063 for more information.

Friends of Halawa Xeriscape Garden, 99-1268 Iwaena St., 527-6113: "How to Xeriscape" class with Mark Takemoto, 9 a.m.-noon July 26. Cost: $2. Registration required. "Ninth Annual Halawa Open House and Unthirsty Plant Sale," 9 a.m.-2 p.m. Aug. 2. Free admission.

Hilo Orchid Society, 1-808-334-1405: 45th annual orchid show, 9 a.m.-5 p.m. today, tomorrow, 9 a.m.-2 p.m. Sunday. Admission: $1.50.

Ho'omaluhia Botanical Garden, 233-7323: Learn about rain forest plants 10 a.m. Saturdays and 1 p.m. Sundays. Free. Bring walking shoes, bug repellent, rain gear and a picnic. Compost workshop, 9:30-11:30 a.m. fourth Saturday of the month. Bring walking shoes, insect repellent, rain gear, work gloves.

Lyon Arboretum, 3860 Manoa Road, Honolulu, 988-7378: Pat Sumida leads a tour of Marugame Nursery, 9:30-11:45 a.m. tomorrow Limited enrollment. Meet at the nursery. Cost: $15.50. Call 988-7378.

Luis Manrique shows how to produce taro at home, 9:30-11:45 a.m. July 26, downstairs classroom. Limited enrollment. Cost: $15.50. Call 988-7378.

Janet Thebaud Gillmar teaches how to grow herbs, vegetables and fruits, 9:30-11:45 a.m. Aug. 2, downstairs classroom. Limited enrollment. Cost: $15.50. Call 988-7378.

"Growing French-Style Vegetables in Hawaii" with Janice Ito, 12:30-2:30 p.m. Aug. 2, downstairs classroom. Limited enrollment. Cost: $15.50. Call 988-7378.

Visit Douglas De Moss Orchids, 9:30-11:45 a.m. Aug. 2, 260 Jack Lane. Limited enrollment. Cost: $15.50. Call 988-7378 or 595-2660.

Annual plant, craft sale, 9 a.m.-2 p.m. Aug. 23, Blaisdell Center. Free admission. Information: 988-7378.