Halawa Xeriscape Garden: 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.

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 to 11 a.m. every fourth Saturday of the month.

Kunia Orchid Society, 623-2571 or 623-6707: 43rd annual orchid show, 9 a.m. to 7 p.m. today and tomorrow, and 9 a.m. to 4 p.m. Sunday, at the Del Monte Kunia Gym.

Lyon Arboretum, 3860 Manoa Road, Honolulu, 988-7378: Betsy Sakata will teach a class on water gardening, 9:30 to 11:45 a.m. tomorrow, downstairs classroom. Limited enrollment. Cost: $15.50 nonmembers, $11 members.

Dean Okimoto shows how to grow and use culinary herbs, 9:30 to 11:45 a.m. March 27, Nalo Farms. Limited enrollment. Cost: $8 nonmembers, $7 members.

Orchid Society of Manoa, 537-3071: Video on orchid pests and diseases, 7:30 p.m. March 26 at Manoa Valley District Park, 2721 Kaaipu Ave.

Wahiawa Botanical Garden, 621-7321: Hands-on gardening, 9 to 11 a.m. Wednesdays. Free.