* Saturday: Plant sale of natives found in the Santa Monica Mountains, 9:30 a.m.-4 p.m., with a free mulching demonstration at 10 a.m., at Soka University Nursery, 26800 W. Mulholland Highway, Calabasas, (818) 878-3763. Free admission.
* Saturday: Class on simple home landscaping, 11 a.m., at Fullerton Arboretum, 1900 Associated Road (at Yorba Linda Boulevard), Fullerton, (714) 278-3404. $7.
* Saturday: Nature crafts for children 3 and older, 1-3 p.m., at the Huntington Botanical Gardens, 1151 Oxford Road, San Marino, (626) 405-2272. Adults, $8.50; seniors, $7; students, $5; children under 12, free.
* Saturday: A talk on creating colorful containers, 10 a.m., at Descanso Gardens, 1418 Descanso Drive, La Canada Flintridge, (818) 952-4401. Adults, $5; seniors and students, $3; children, $1.
* Saturday-Sunday: "Orchid Rodeo" (show and sale), 9 a.m.-6 p.m. Saturday, 10 a.m.-5 p.m. Sunday, at South County Regional Center, 800 W. Branch, Arroyo Grande (near Pismo Beach), (805) 929-1791. $1.50.
* Sunday: Seminar on fragrance in the garden with herb expert Shirley Kerins and salvia expert Betsy Clebsch, 1-3:30 p.m., at Descanso Gardens, 1418 Descanso Drive, La Canada Flintridge. $18. Reservations required: (818) 952-4401.
* Wildflower hotline: If you want to know what wildflowers are blooming where in the Southland, you can call the Wildflower Hotline of the Theodore Payne Foundation in Sun Valley. The 24-hour hotline is (818) 768-3533. It is updated each Thursday at 7 p.m. and will be in operation until May 27. You can also subscribe to the group's FlowerE(mail) for $20 or FlowerFax for $50. These publications also list the best flower-viewing spots and the wildflowers you're likely to discover. To subscribe or learn more, call (818) 768-1802.