Krystian Wetulani, 32, who owns three shops, said he felt he was stuck in red tape. Only one of his shops has been approved, and he is appealing a denial for another. Fines are mounting while he seeks locations that will conform to regulations. “It’s impossible,” Mr. Wetulani said. “Landlords hear the word ‘weed’ and just say no.”

In the Downtown Eastside, a gritty Vancouver neighborhood, a crowd of people were smoking crack and shooting heroin on the sidewalk outside Farm, a dispensary with a self-avowed social-justice mission. It employs only women, many of them immigrants, former prostitutes or victims of sexual assault, and its proceeds help finance neighborhood programs like needle collection and a community garden.

The city tolerates open use of illegal drugs in the neighborhood and a local safe-injection site for heroin users, but Farm still fell afoul of the distance restrictions in the new marijuana regulations, and had to win an appeal to stay open.

Wang Jingzhi, 83, an immigrant who lives in the nearby Chinatown neighborhood, said she frequently bought marijuana from Farm to soothe the aches and pains of old age. “Whenever I smoke it, my whole body feels better,” she said in Chinese.

Like many in the local marijuana business, Cait Hurley, 28, the dispensary’s manager, said she was worried that new government regulations would favor corporate interests and exclude women and the working class. “There’s a lot of fear this will all be taken away from us,” she said.

Under Mr. Trudeau’s conservative predecessor, Stephen Harper, the government stripped patients of the right to grow their own medical marijuana in 2013, and centralized production and distribution through a few licensed companies. But in February, a federal court reinstated patients’ growing rights; the new rules announced on Aug. 11 put that ruling into effect.

Facing greater competition, the 34 government-licensed producers are calling for everyone to be held to the same rules they must follow, said Colette Rivet, the executive director of a producers’ trade association, Cannabis Canada. “We would be shut down if we tried to sell to dispensaries,” Ms. Rivet said.