The Army discovered it was inadvertently growing marijuana on the property in June. Since then, they have picked about 100 low-grade marijuana plants. Called "ditch weed" or "feral hemp," the plant grows wild in some places, including Kansas where the mulch supplier is located.
The Rocky Mountain Arsenal was used by the Army as a chemical weapons manufacturing facility during World War II and the Cold War. As part of a clean-up effort, the Army had been reseeding in some areas. But when the seeds started to grow, they noticed they were reseeding the area with marijuana.
CBSNews.com Special Report: Marijuana Nation
Charlie Scharmin is in charge of the cleanup. He said he was quite surprised when he was told what was growing at the arsenal.
"It's not something you expect in an environmental cleanup job," Scharmin told CBS News. "It was a little surprising."
Scharmin says they plan to mow, burn or maybe even have bison who roam on the land eat the rest.
"(The) Fish and Wildlife Service does not seem to have any concern about having bison out there (with the plant present)," Scharmin said.