Standing in a garden of native plants on the University of Delaware campus, UD professor Douglas Tallamy puts his hand on an oak tree, one of the many species he hopes to encourage people to grow in their own yards.

“It’s a grassroots solution, and the goal is to convert 50 percent of the area that’s in lawns now to functional ecosystems,” Tallamy said.

Tallamy started the nonprofit Homegrown National Park with the help of Michelle Alfandari in the fall of 2020. The organization helps homeowners transform their yards from plots with nothing but grass into ecosystems full of native plants like the ones at UD.

“It’s our effort to reach beyond the choir,” Tallamy said. “I’ve been lecturing to the choir for 15 years, a choir of people who already get it.”

Tallamy met Alfandari when she attended a talk he gave in Connecticut about biodiversity.

“He motivates you to take action by telling you that you are empowered to turn this around to regenerate biodiversity,” Alfandari said.

Homegrown National Park’s website has an interactive map showcasing individuals who have contributed to the project by turning their yards into homes for native plants. The site currently counts over 11,000 participants.

Tallamy’s goal is to move the focus of conservation from public lands, like national and state parks, to private land, which represents the vast majority of land in the U.S. He said 78 percent of land in the United States is privately owned, with 86 percent of land east of the Mississippi being privately owned.

“For this to work, you need to reach tens of millions of people – all the people who don’t have any clue that their little piece of earth is important for the future of this country,” Tallamy said.

He said the health of an ecosystem can be measured by the number of caterpillar species, because caterpillars are an important food for birds. Approximately 96 percent of birds raise their young on insects.

“Most of those insects are caterpillars,” Tallamy said. “So you get rid of your caterpillars, you’ve gotten rid of your birds.”

Tallamy said there are four things every ecosystem needs to accomplish: sequester carbon dioxide, manage the watershed, support the local food web and support pollinators.

“A lawn does none of those,” Tallamy said. “It’s the worst plant for carbon sequestration. It destroys watersheds rather than manages them. It doesn’t support any pollinators, and it doesn’t support any food webs.”

His latest book, “The Nature of Oaks: The Rich Ecology of Our Most Essential Native Trees,” published in 2021, focuses on oaks because the native species supports over 950 species of caterpillars, far more than other trees.

The problems facing Delaware’s ecology – climate change, the extinction crisis, overpopulation of deer and invasive species – are all linked together. Humans and nature cannot exist separately, Tallamy added, since our actions impact areas like White Clay Creek State Park that are often considered pristine untouched nature.

“You go to White Clay Creek, walk around, and over a third of that vegetation is from China,” Tallamy said.

Tallamy’s interest in conservation began when he was in third grade and a bulldozer filled in a pond near Tallamy’s childhood home, killing his favorite toads.

“I pursued it in the same way that everybody did,” Tallamy said. “I thought we had to preserve what wasn’t wrecked yet. I never once thought about enhancing our yard where I lived. It never occurred to me. Nature was someplace else.”

Tallamy’s shift toward public advocacy started when he moved to Oxford, Pa., and saw how invasive plants covered his lawn. He worked with an undergraduate conducting research into how invasive plants damage the food web for insects, which in turn hurts bird populations. An article on his research got picked up by the Associated Press, leading to a bird club in Pennsylvania inviting him to give a speech.

“My message is that you can help turn this around,” Tallamy said. “People get excited about that. I get four talk requests a day now.”

Tallamy’s own garden is a testament to native plants, with 10 species of oaks living along with 120 genera of woody plants on his 10-acre property in Oxford.

Newark Neighbors is a biweekly column that spotlights everyday Newarkers who have an interesting story. Know somebody who should be featured? Contact reporter Matt Hooke at

Load comments