For 12 years, professional landscapers have volunteered their time and resources for a special day of renewal and remembrance at Arlington National Cemetery.

For the third year in a row, Bob Dobson has come to help restore the natural beauty of Arlington National Cemetery. Dobson and other contractors worked to an install an irrigation system around the veteran rose garden. "I was a Vietnam veteran, so coming down here and being able to volunteer has special meaning because of that," said Dobson.

Dobson is one of the hundreds of members of Planet, the professional land care network, who converged on the more than 600 acres of the cemetery Monday as part of the annual day of renewal and remembrance.

They pack up their trucks or get on an airplane and fly here on their own," said Jason Cupp, President of Planet.

"Its nice to give back in some small way for the sacrifices that have been made by our Armed Forces," said Tim Malooly.

Tagging along with his daughter's landscape company, World War II veteran Wilfred Doerfler was at the event for the first time. He said coming back to Arlington brought back memories of the time he served overseas. Like many others, he said he has a special connection with the cemetery, many of his colleagues are buried here.

The work and labor, worth nearly $350,000, will help keep the national landmark pristine for years to come.

"To be able to come back years after we've done the work and watch the plants mature and maintain -- that's rewarding," said Dobson.

The work at Arlington was not the final stop for the members of Planet. Tuesday they will head to Capitol Hill to talk to Congressmen about green issues that affect their industry.