For gardeners and other plant-lovers, here's a sampling of regional events:

5K Run for Clean Air Cash prizes, contests, food. Martin Luther King Dr.; 5krunforcleanair.org. 4/21. 9 am-12 pm.

Bird Walks Sat. Call 215-345-7860 for more information. Peace Valley Nature Center, 170 Chapman Rd., Doylestown. Donation suggested: $2. 4/21.

Birding With Ruth Bird walk led by experienced area birdwatcher Ruth Pfeffer. Norristown Farm Park, 2500 Upper Farm Rd., Norristown; 610-270-0215. www.birdingwithruth.com. 4/26.

  • Darby Creek Clean-Up Help clean Darby Creek. John Heinz National Wildlife Refuge at Tinicum, 8601 Lindbergh Blvd. Registration required: 215-365-3118. 4/21. 8 am-12 pm.
  • Earth Day at Newlin Grist Mill Help the park get ready for the spring & summer. Newlin Grist Mill, 219 S. Cheyney Rd., Glen Mills; 610-459-2359. 4/22. 1-4 pm.
  • Earth Day Edibles Guided walk with focus on edible & medicinal plants. Lorimer Park, 183 Moredon Rd., Huntingdon Valley. Registration required: 215-947-3477. 4/22. 2 pm.
  • Gardening Lecture With Suzanne Smith-Oscilowski Presentation on sustainable gardening practices & the benefits of using native plants in your yard. Wissahickon Valley Watershed Association, 12 Morris Rd., Ambler. Reservations suggested: 215-646-8866. 4/20. 6:30 pm.G
  • Going Native Program on native plants & invasive species. Bellevue State Park, 800 Carr Rd., Wilmington. Registration required: 302-761-6963. $5. 4/22. 2 pm.
  • Green Roof Guided Tour Tour of the arboretum's 3 "green" roofs. Swarthmore College — Scott Arboretum, 500 College Ave., Swarthmore; 610-328-8025. 4/24. 12:30 pm.
  • Help Maintain the Rose Gardens Help deadhead, weed & trim the rose gardens. Glen Foerd on the Delaware, 5001 Grant Ave. 4/21.
  • Herb Society of America Presentation on native plants & herbs. Scotland Run Nature Center, 980 W. Academy St., Clayton. 4/22. 1:30 pm.
  • Home Gardeners' School Presentations on a variety of gardening-related subjects & master gardener marketplace with plants, art & jewelry. Penn State Great Valley, 30 E. Swedesford Rd., Malvern; 610-690-7669. $55; 4/21. 8 am-2 pm.
  • How Our Gardens Change Lecture/garden walk series exploring how Mount Cuba's gardens change over several months. Mount Cuba Center, 3120 Barley Mill Rd., Hockessin, Del. Registration required: 302-239-4244. $20. 4/20.
  • Knowing Native Plants: Late Spring Lovelies Presentation on later-blooming spring wildflowers, followed by an outdoor tour. Bowman's Hill Wildflower Preserve, 1635 River Rd., New Hope. Registration required: 215-862-2924. $20. 4/21. 10 am-1 pm.
  • Master Gardeners of Camden County Plant Clinic Opportunity to get gardening questions answered or sick plants diagnosed. Rutgers Cooperative Extension of Camden County, 1301 Park Blvd., Cherry Hill. 4/21.
  • Native Plant Sale Featuring high-quality native trees, shrubs, wildflowers, ferns & grasses. Wissahickon Valley Watershed Association, 12 Morris Rd., Ambler; 215-646-8866. 4/21. 9 am-12 pm.
  • Pansy Picnic Shopping event with music, finger foods & champagne. Ten percent of nursery purchases benefit the William Way Community Center. Greensgrow Farms, 2501 E. Cumberland St. 4/22. 12-4 pm.
  • Practical Landscape & Garden Tips for a Tough Economic Time Presentation on inexpensive landscape & garden ideas. Burlington County Library — Evesham Branch, 984 Tuckerton Rd., Marlton. Registration required: 856-983-1444. 4/22. 2 pm.
  • Seedlings Nature-themed play activities for young kids. The Schuylkill Center, 8480 Hagy's Mill Rd.; 215-482-7300 x 110. $8. 4/23.
  • Sharing Nature With Your Child Presentation on gardening projects for children & how to make your yard kid-friendly. Delaware Center for Horticulture, 1810 N. Dupont St., Wilmington; 302-658-6262. $15. 4/23. 5:30-7 pm.
  • Spring Bird Walk Take a walk through the preserve with local birding guides with a chance to see a variety of species, including warblers, thrushes, towhees, goldfinches, chickadees, woodpeckers and more. Departs from the visitor center; binoculars recommended. Bowman's Hill Wildflower Preserve, 1635 River Rd., New Hope; reserve at 215-862-2924. www.bhwp.org. 4/21.
  • Spring Into Action Volunteers are needed to get the park ready for summer. Ralph Stover State Park, State Park Rd., Pipersville. Registration required: 610-982-0161. 4/21. 9:30-3 pm.
  • Spring Wildflower Tour Mount Cuba Center, 3120 Barley Mill Rd., Hockessin, Del. Registration required: 302-239-4244. $5. 4/20.
  • Susan Conner: My Garden Collection Recent oils of gardens, parks & preserves. Delaware Center for Horticulture, 1810 N. Dupont St., Wilmington; 302-658-6262. 4/20.
  • Trilliums of Mount Cuba Center Tour of the center's trillium collection. Mount Cuba Center, 3120 Barley Mill Rd., Hockessin, Del. Registration required: 302-239-4244. $20. 4/25. 10 am-12 pm.
  • Urban Farm Planting Day Help plant beets, carrots, lettuce & other veggies at Wilmington's only urban farm. Delaware Center for Horticulture, 1810 N. Dupont St., Wilmington. Registration required: 302-658-6262. 4/21. 10 am-1 pm.
  • Weekly Wednesday Walkabouts The arboretum's horticulture staff leads a series of guided spring walks. Jenkins Arboretum, 631 Berwyn Baptist Rd., Devon. Reservations requested. 4/25.

Send information about gardening and horticultural events to gardenscoop@phillynews.com. Include a contact phone number and send at least two weeks before the event.