If you're an agency thinking about bringing on a recreational marijuana client, the first thing you should know is not to talk about "marijuana." Clients prefer the term "cannabis," according to agency executives already having these conversations, probably because it doesn't have the same negative connotations and is far away from the stoner undertones of "weed," or heaven forbid, "pot." Cannabis almost sounds artisanal by comparison.

"We don't want to be the weed guys," said Wexley School for Girls CEO Cal MacAllister.

That might be the smallest issue facing agencies considering work in the sector as restrictions on the growth, sale and use of marijuana loosen in Colorado and Washington State.

Wexley School for Girls, which is based in Seattle, is currently in a pitch for a recreational cannabis client, but the industry is "full of landmines," Mr. MacAllister said. Fifteen marijuana companies have approached his agency, according to Mr. MacAllister, but only two had serious business models.

Max Lenderman, the CEO of Boulder, Colo.-based School, initially signed a cannabis client, Aspen-based Silverpeak Apothecary. The company had a marketing budget of about $300,000, and School based its advertising on the "Prohibition is over" idea, drawing parallels between the legalization of marijuana and the legalization of alcohol for ads that ran in print and online.

"When Prohibition was over, nobody knew what Canadian Club was," said Mr. Lenderman. "Those budgets are going to get bigger and bigger, and the race is on to become the most trusted brand in this space."

But the agency resigned the Silverpeak account a few weeks ago, according to Mr. Lenderman. He said the client wasn't "pushing hard enough on the social responsibility and safety piece," something he said he considers necessary in a cannabis marketer.

Silverpeak Apothecary did not respond to messages left requesting comment.

(UPDATE: After this article was published, Silverpeak owner Jordan Lewis said his company has always been focused on social responsibility and safety. He said education has been a core tenet of the business in order to ensure customers understand the proper use of marijuana and its risks. He said Silverpeak has invested more than $40,000 in educational materials and has been providing a pamphlet with guidelines about responsible consumption, for example. The company has also helped fund the Valley Marijuana Council, a community organization in Aspen led by Pitkin County Sheriff Joe DiSalvo created to help address fears around marijuana. Mr. Lewis said Silverpeak and School had a disagreement over whether School was meeting Silverpeak's expectations.)

Grenadier, another Boulder shop, said no thanks when approached with a cannabis opportunity, said Jeff Graham, partner at the agency. It passed not because marijuana is "categorically evil" but because the sector doesn't feel figured out as a business. "Take the ethics and morality out of it," Mr. Graham said. "It's a cash-only business. These companies can't even get bank accounts. How are we going to get paid?"

More mainstream clients might also hesitate to share an agency roster with a marijuana retailer. Grenadier is agency of record for Winter Park Ski Resort, but marijuana is a huge liability issue for ski areas, which are trying to control its use on the slopes.

In Washington State, where recreational marijuana will start to be sold in the coming months, Possible Worldwide CEO Shane Atchison is firmly against bringing on these clients. One reason is "pragmatic": "Can these guys afford the caliber of the work we do?" And the other is ethical or legal, because it's still unclear how the federal government is going to proceed. Federal agencies could perhaps clamp down on profits stemming from taking on marijuana sellers.

That could change relatively soon, of course "It's so early now, weed is so marginalized, but in a year or two, it might be more relaxed, and become the norm," Mr. Atchison said. If a cannabis client approached Possible with the aim of building a brand over the long term, that might make sense, he said.

In New York, Horizon Media is one agency that has been working with a somewhat controversial client -- e-cig brand NJoy. Would it take on weed? "In my opinion, I would probably poll my management team," said CEO Bill Koenigsberg. And if there weren't any serious objections, he's not averse to taking on a cannabis client -- if the law's okay with it. There's one potential problem, though: "We do sample a bit of every client's product when we start handling it," he said.

UPDATE: Horizon Media said the company is open to speaking with somewhat controversial brands where appropriate, however a number of brands or products, such as cannabis, would not be approved by the management team given its potential for misuse and abuse.