PORTLAND — Wildfires scorching hundreds of acres in Southern Oregon are prompting evacuations, canceling popular performances of the Ashland Shakespeare Festival and casting a smoky cloud over the region’s most famous crop.

Marijuana growers say the wildfires have turned what normally would be the sun-drenched end of summer into a smoky haze that has affected their plants and field workers.

“The smoke down here is choking out everything,” said Brent Kenyon, a longtime marijuana grower in Eagle Point who owns Oregon Cannabis Farms.

He said the haze has covered the crop like a “plastic layer” sealing out direct sunlight as the plants head into its critical flowering stage.

Michael Monarch, owner of Epic Family Farms in Talent, Ore., said he sent field workers home early on Wednesday because of poor air quality.

“The smoke is not fun at all,” he said. “We are wearing masks and dealing with the carbon in the air.”

Jackson and Josephine counties make up the epicenter of outdoor marijuana production in Oregon. The Oregon Health Authority’s latest statistics show that the counties are home to nearly 10,000 registered medical marijuana growers; the Oregon Liquor Control Commission said another 264 licensed recreational producers operate in the county.

The Miller Complex is burning more than 12,000 acres near the border of Jackson and Josephine counties. The fires are active but moving slowly, according to authorities. Dense smoke and poor air quality are expected to persist for now. An evacuation order has been issued for an area of the Applegate Valley.

Fire and smoky conditions are expected to linger into early fall — or until the region sees a good rainstorm, said Brian Ballou, a spokesman for the Incident Information System, an interagency clearinghouse for wildfire information.

“The best thing anyone can hope for is a really good, wetting rain storm,” he said.

For most growers, the problems posed by the fires are a nuisance, said Cedar Grey, whose company grows hemp and cannabis.

Grey said the wildfires are a topic of conversation among growers, but their concerns are less about their crops and more about losing homes to fire. One fire that’s part of the Miller Complex isn’t far from Gray’s home.

“This is one of the worse years we have ever had for sure,” he said. “At this point I think most of the growers that are impacted are medical growers who are living very rurally, but the fires are coming closer to the center of communities.”