05/23/2026
In 2020, University of Delaware entomologist Doug Tallamy and his co-founder Michelle Alfandari launched a project that sounds almost too modest to matter: an interactive online map where individual homeowners could register their native plantings and watch a "firefly" light up at their location.
Five years later, the Homegrown National Park map has logged more than 170,000 acres of native plantings across the United States and Canada, representing tens of thousands of individual yards, hundreds of partner organizations, and a growing network of community groups, churches, schools, libraries, and municipalities that have collectively built something larger than most national parks in the lower 48.
Yellowstone is 2.2 million acres. Glacier is 1 million. Great Smoky Mountains is 522,000. Acadia is 49,000. Voyageurs is 218,000. The Homegrown National Park sits, today, between Acadia and Voyageurs in total scale — assembled almost entirely from suburban front yards, side yards, parking medians, schoolyards, churchyards, and the strips of land between sidewalks and curbs that nobody in formal land-use planning ever thought of as habitat.
The premise underlying the project is mathematically simple. The United States has 44 million acres of lawn — bigger than New England — most of which Tallamy calls an "ecological deadscape," supporting almost no insect life because Kentucky bluegrass and other turf monocultures evolved on a different continent and host virtually no native caterpillars.
Caterpillars are the foundation of the food web that supports songbirds: a single chickadee nest requires 6,000 to 9,000 caterpillars to fledge.
North America has lost 3 billion breeding birds since 1970. The collapse of insect populations is happening in parallel. Tallamy's calculation was that if half of America's 44 million acres of lawn were converted to native plants, the resulting habitat would exceed the combined area of every major national park in the contiguous United States.
Homegrown National Park is the structured, measurable, gamified version of that idea. Anyone can register at homegrownnationalpark.org. The map shows, in real time, where the network is densest and where it's still thin.
State-level rankings create a friendly competition. Affiliated organizations like Wild Ones, garden clubs, native plant societies, and conservation land trusts plug into the same framework.
The 170,000-acre figure understates the actual impact, because many participants don't register, and many native-plant conversions happen without ever being mapped. But the registered figure is enough to make a point.
The largest national park in America is now being built, one front yard at a time, by people who never asked permission. They just planted milkweed, registered the location, and waited for the butterflies.
