On Osage Street in Coon Rapids, Mary Weise deals with cottonwood every year.
'Fills your whole yard. Fills your air conditioner," said Weise.
She also knows it's combustible.
"It can start a fire," she said.
That's keeping local fire department busy. Coon rapids Fire posted a warning on Facebook Saturday night after responding to several fires including one at Wildwood Park where cottonwood fluff was a factor.
Sunday firefighters demonstrated how quickly it can spread once ignited.
"Acts like an accelerant," said Nick House with the Coon Rapids Fire Department. "Going to close to homes starting homes on fire starting decks on fire."
In Bloomington Saturday, firefighters say someone trying to get rid of the cottonwood, set fire to it which spread to a nearby home.
"Don't light it on fire," said House.
Coon Rapids Fire is reminding people to be cautious with their cigarettes and also recreational fires near cottonwood.