Cost: Medium ($100 to $500)
Green Impact: 4 out of 5
Whether you're looking to spruce up a neglected tree well or the strip of dirt between the curb and the sidewalk, most cities encourage residents to beautify public land.
To "adopt" an area, contact your local parks and recreation office, department of environmental protection, or greening organization, such as MillionTreesNYC in New York or Friends of the Urban Forest in San Francisco.
Some Rules of (Green) Thumb
Find the Right Location
Choose a spot with sufficient sunlight. If you want to plant around a tree, select one that's less than a year or two old to avoid damaging extensive root systems.
Pick Hearty Plants
Look for drought- and dog-resistant species. Your local USDA cooperative extension service can suggest the best plants for your region (find yours at nifa.usda.gov/extension), but here's a list to get you started:
Prep the Soil
Remove weeds. "If it feels hard or sandy, you'll want to add some compost," says Annie Spiegelman, a veteran guerrilla gardener and the author of "Talking Dirt." "It will decompose over time and feed the plants naturally."
Don't Forget Water
An existing irrigation system or nearby water source will make the plants easier to maintain in the months and years ahead.
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