The number of people aged 50 and older reporting marijuana use in the prior year went up from 1.9 percent to 2.9 percent from 2002 to 2008, according to surveys from the Substance Abuse and Mental Health Services Administration.
The rise was most dramatic among 55- to 59-year-olds, whose reported marijuana use more than tripled from 1.6 percent in 2002 to 5.1 percent.
Observers expect further increases as 78 million boomers born between 1945 and 1964 age. For many boomers, the drug never held the stigma it did for previous generations, and they tried it decades ago.
Some have used it ever since, while others are revisiting the habit in retirement, either for recreation or as a way to cope with the aches and pains of aging.
Siegel walks with a cane and has arthritis in her back and legs. She finds marijuana has helped her sleep better than pills ever did. And she can't figure out why everyone her age isn't sharing a joint, too.
"They're missing a lot of fun and a lot of relief," she said.
Politically, advocates for legalizing marijuana say the number of older users could represent an important shift in their decades-long push to change the laws.
"For the longest time, our political opponents were older Americans who were not familiar with marijuana and had lived through the 'Reefer Madness' mentality and they considered marijuana a very dangerous drug," said Keith Stroup, the founder and lawyer of NORML, a marijuana advocacy group.
"Now, whether they resume the habit of smoking or whether they simply understand that it's no big deal and that it shouldn't be a crime, in large numbers they're on our side of the issue."
Each night, 66-year-old Stroup says he sits down to the evening news, pours himself a glass of wine and rolls a joint. He's used the drug since he was a freshman at Georgetown, but many older adults are revisiting marijuana after years away.
"The kids are grown, they're out of school, you've got time on your hands and frankly it's a time when you can really enjoy marijuana," Stroup said. "Food tastes better, music sounds better, sex is more enjoyable."
The drug is credited with relieving many problems of aging: aches and pains, glaucoma, macular degeneration, and so on. Patients in 14 states enjoy medical marijuana laws, but those elsewhere buy or grow the drug illegally to ease their conditions.
Among them is Perry Parks, 67, of Rockingham, N.C., a retired Army pilot who suffered crippling pain from degenerative disc disease and arthritis. He had tried all sorts of drugs, from Vioxx to epidural steroids, but found little success. About two years ago he turned to marijuana, which he first had tried in college, and was amazed how well it worked for the pain.
"I realized I could get by without the narcotics," Parks said, referring to prescription painkillers. "I am essentially pain free."
But there's also the risk that health problems already faced by older people can be exacerbated by regular marijuana use.
Older users could be at risk for falls if they become dizzy, smoking it increases the risk of heart disease and it can cause congnitive impairment, said Dr. William Dale, chief of geriatrics and palliative medicine at the University of Chicago Medical Center.
He said he'd caution against using it even if a patient cites benefits. "There are other better ways to achieve the same effects," he said.
Pete Delany, director of applied studies at the Substance Abuse and Mental Health Services Administration, said boomers' drug use defied stereotypes, but is important to address.
"When you think about people who are 50 and older you don't generally think of them as using illicit drugs — the occasional Hunter Thompson or the kind of hippie dippie guy that gets a lot of press maybe," he said. "As a nation, it's important to us to say, 'It's not just young people using drugs it's older people using drugs.'"
In conversations, older marijuana users often say they smoke in less social settings than when they were younger, frequently preferring to enjoy the drug privately. They say the quality (and price) of the drug has increased substantially since their youth and they aren't as paranoid about using it.
Dennis Day, a 61-year-old attorney in Columbus, Ohio, said when he used to get high, he wore dark glasses to disguise his red eyes, feared talking to people on the street and worried about encountering police. With age, he says, any drawbacks to the drug have disappeared.
"My eyes no longer turn red, I no longer get the munchies," Day said. "The primary drawbacks to me now are legal."
Siegel bucks the trend as someone who was well into her 50s before she tried pot for the first time. She can muster only one frustration with the drug.
"I never learned how to roll a joint," she said. "It's just a big nuisance. It's much easier to fill a pipe."