(CNN)Congressional Cemetery is the final resting place of more than 68,000 so called 'permanent residents' with a distinguished list that includes J. Edgar Hoover - the former FBI director - and John Philip Sousa - the famed composer. But the caretakers here have a problem: invasive species that threaten this historic landmark.
The goats who help keep Congressional Cemetery clean
So instead of using harmful herbicides, they came up with an inventive solution: goats.
On the menu for the grazers: poison ivy, poison oak, poison sumac, kudzu and English ivy.
"They're plants that are not native to Washington, DC." says Paul Williams, President of Historic Congressional Cemetery, "What happens is that goes up and it kills our trees. And then the trees fall onto the cemetery, damaging our headstones."
With its first burial in 1807, Washington Parish Burial Ground eventually became known as "Congressional Cemetery". Mathew Brady, a civil war photographer, Anne Royall, who is considered to be among the first professional female journalist and Elbridge Gerry, the signer of the Declaration of Independence from whose name was derived the political term "Gerrymander" are all important individuals that rest here.
Conserving the grounds is an important task and goats play a role in its upkeep. "They are so close to the Anacostia River, they didn't want anything running off into the river and they have a hive here."says Mary Bowen, President of Prosperity Acres from Sunderland, Maryland. "So getting rid of the unwanted vegetation now lets the native plants grow which then continues to support the pollinators."
"What's great is the herd of 30 goats costs about $5,000 for two weeks," says Williams. "It sounds like a lot of money but when you break it down, it's about a dollar a goat per hour. So you can't beat that labor rate!"