▪ Cheer the crews to the finish line at the 26th annual Cardboard Boat Regatta at Six Flags Hurricane Harbor on Saturday. The event, benefiting the River Legacy Living Science Center, will be 9 a.m.-4 p.m. Tickets are $8 at the door. The center will be closed Saturday. www.riverlegacy.org.
▪ A spring plant sale by the Tarrant County Master Gardeners is scheduled for 9 a.m.-2 p.m. Saturday at the Community Demonstration Gardens at the Tarrant County Resource Connection, 1801 Circle Drive, Fort Worth. Activities include an “Ask a Master Gardener” table, tool sharpening, presentations on bees, composting and more. Bring a wagon or cart. http://www.tarrantmg.org.
▪ The Spring Festival in the Japanese Garden is set for Saturday and Sunday in the Fort Worth Botanic Garden, 3220 Botanic Garden Blvd. Hours are 10 a.m.-5 p.m. Saturday and 11 a.m.-5 p.m. Sunday. Admission is $6, $3 for children ages 4-12.
▪ A free class on organic fertilizer and mycorrhizal fungi will be at 10 a.m. Saturday at Trinity Haymarket, 1715 Market Center Blvd., Dallas. To reserve a seat, call 214-202-2163.
▪ Learn about easy-care flowers during a free clinic at 10:15 a.m. Saturday at all area Calloway’s stores. www.calloways.com.
▪ Gailon Hardin, of the North Central Texas chapter of the Native Plant Society of Texas, will speak about native plants at 10:30 a.m. Saturday at Redenta’s Garden, 5111 W. Arkansas Lane, Arlington. 817-451-2149; www.redentas.com.
▪ The 10th annual Prairie Fest will be 11 a.m. to sunset Saturday in the Tandy Hills Natural Area, 3400 View St., Fort Worth. Offerings include wildflower walks, storytellers, green activities, food booths, live music and more. www.tandyhills.org.
▪ Be a nature detective during “Tracks, Scats and Signs,” 1-3 p.m. Saturday at the Fort Worth Nature Center and Refuge. Learn about “Amazing Armadillos” at 1:30 and 3 p.m. Sunday. Both activities are free with admission ($2-$5). 9601 Fossil Ridge Road, Fort Worth. 817-392-7410; www.fwnaturecenter.org.
▪ Hummingbird expert George McBride will talk during a meeting of the Arlington Organic Garden Club at 7:30 p.m. Thursday at the Bob Duncan Center, 2800 S. Center St., Arlington. Social time begins at 7. For more information, contact Bob Ressl, 817-265-0696.
Mark your calendar …
▪ For the Colleyville Garden Club’s spring plant sale, 9 a.m.-2 p.m May 2, at the Historic Webb House, 408 Sheton Drive, Colleyville. www.colleyvillegardenclub.com.
▪ For Azle’s biennial Green Scene Garden Tour, noon-4:30 p.m. May 3. Tickets are $15 each; for ticket sale locations or information about sack lunches or the “pop-up shop,” call the Azle Chamber of Commerce, 817-444-1112, or visit www.azlechamber.com.
▪ For the Fort Worth Nature Center and Refuge’s Buffalo Boogie Fun Run, May 9. To register, visit www.fwnaturecenter.org.