Foster Botanical Gardens, 522-7060: Spring plant sale, 9 a.m. to 4 p.m. May 10. Sponsored by the Friends of Honolulu Botanical Gardens. Free. Call 537-1708.
Halawa Xeriscape Garden, 527-6113: "Native Plant Propagation Class" by Mary Wickenden, 10 a.m., May 10. Registration required.
Free admission to garden of dry-land plants at Halawa Industrial Park 10 a.m. to 2 p.m. Saturdays and Wednesdays. Guided tours are free on Thursdays and the last Saturday of each month; call 527-6113 for an appointment.
Plant sale: Foster Botanical Gardens annual plant sale, 9 a.m. to 4 p.m. May 10. Fifty vendors offering orchids, anthuriums, roses, heliconias, hybrid ti, ferns, bromeliads, cactus and succulents. There also will be books, ceramics, and woven and bamboo crafts, and classes on bonsai, orchids, taro and mango grafting. A silent auction will be held intermittently from 9:45 a.m. to 2:30 p.m. Free. Call 522-7065.
Orchid show: 10 a.m. to 4 p.m. May 10 at Koko Marina. Rea Fox and Joann Miles will entertain, 11 a.m. to 1 p.m. There will also be lei making and orchid culture demonstrations. Free.
Waianae Mall: 14th annual Honolulu Rose Society Show, May 10. Everyone is invited to bring their roses to enter the novice category. There will also be a drawing for a round-trip airfare for two on Mahala Air, two nights in a deluxe ocean front room with a breakfast buffet at the Royal Kona Resort, and prizes from mall merchants. Entry forms are available at Waianae Mall merchants' stores. Winning entries will be awarded on May 10. Also, there will be Hawaii-made arts and crafts and a display of entries from the "Why My Mom Is Special to Me" essay contest by Waianae Elementary School students. Information: 737-4676 ext. 4.
Ho'omaluhia Botanical Garden, 233-7323: Volunteer training program for people interested in becoming nature tour leaders, 9:30 to 11:30 a.m. Saturdays, through May 17.
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 to 11:30 a.m. every fourth Saturday of the month. Bring walking shoes, insect repellent, rain gear and work gloves.
Urban Garden Center, 453-6050: Gardening series classes 9:30 to 11:30 a.m. Wednesdays, 962 Second St. Topics include: gardening in the tropical environment, May 14; anthuriums, May 28; dry taro, June 4; lychee, June 18; mango trees, June 25; sweet potato, July 16; eggplant, July 23; and flowering heliconia and ginger, July 30. Costs $5. Call for a registration form.
Wahiawa Botanical Garden, 621-7321: Hands-on gardening, 9 to 11 a.m. Wednesdays. Free.
Waipahu Orchid Association, 453-6566: Orchid care demonstration and plant sale, 10 a.m. to noon May 10, Pearl City Library meeting room. Proceeds will benefit future library programs.