More about weeds

City of Boulder Integrated Pest Management Program:

Colorado State University Extension:

Add this to the list of phenomena that can be attributed to the particularly wet and wintry spring the Front Range has witnessed in 2013: a seeming bumper crop of dandelions and other weeds.

But appearances can be deceiving. It is the timing of the weeds' debut, rather than the quantity, that makes this year noteworthy.

"We had a lot of moisture in April, so you're going to have a lot of weed growth coming, here in May," said Jim Klett, a professor and Cooperative Extension landscape horticulturalist at Colorado State University.

Boulder saw 47.6 inches of snow in April, easily topping the record for the month, which was 44 inches, set in 1957. And it didn't end there, with another 12.1 inches of snow being dumped on the city May 1 and that morning's low of 17 degrees setting a new May record for the city.

That late burst of winter left spring with a lot of quick catching up to do.

"I wouldn't say it's a more robust dandelion year," Klett said. "I think people are just observing them more because they're all coming at once."


The effects of such a wintry spring on the Front Range go well beyond a sudden -- and, for many, unwelcome -- bloom of yellow in homeowners' yards.

"That moisture was well needed, and basically, all the trees are very late; because of the freeze we had in April their buds got killed," Klett said. "There are going to be secondary buds. They are going to be late, but now things will move very quickly, and that's where you're also going to see a lot of weed growth come."

The piles of snow in April, supplemented by the final dose at the start of May, kept many people from mowing their lawns as early as they otherwise might have. The moisture supercharged the dormant weeds, and now the sudden warmth of recent days is causing everything to pop at once.

"It just seems like, to me, we had a pretty extended winter and now we have jumped pretty close to summer," said Steve Wilke, a garden department sales representative at Boulder's McGuckin Hardware. "Things are in full swing now. In a week and a half or so, things have really taken off, as far as dandelions and that stuff goes."

"I have noticed that they are everywhere right now," Rell Abernathy, integrated pest management coordinator for the city of Boulder, said of the dandelions. "When it warmed up, it caused a flush to happen pretty much at once, and everything is growing. People haven't been able to mow, and I think that has amplified it."

Those who feel challenged in keeping their weeds down might be happy not to be in Abernathy's shoes.

"We like to keep the managed turf areas as weed-free as possible, but we have 600 acres of parks in the city, and so we put the efforts in the areas where it's really important," she said. "Weeds can be an issue on athletic fields, where you can trip or slip, and so you want a certain quality of turf on certain areas."

The city's practice is to use pesticides or herbicides only as a last resort after exhausting all other options in its weed suppression. And if chemicals are used, the least toxic option is chosen from a list of products that has been reviewed, evaluated and approved by its integrated pest management subcommittee.

"No turf areas in our parks have had any herbicides on them for 11 years, and even before that, it was very minimal," said Lisa Martin, urban parks manager for Boulder's Parks and Recreation department.

In addition, six Boulder parks are designated as "organic," meaning that even synthetic fertilizers are not applied to either the turf or any other facet of their landscapes. In those parks the city instead uses what Martin referred to as "a heightened level of cultural practices," including aeration and over-seeding. Those parks are Greenleaf Park, Columbine Park, Shanahan Ridge Park, Foothills Community Park, Stazio Ballfield No. 3 and the Boulder Municipal Complex.

Abernathy recommends that homeowners fight the good fight against weeds, and keep their children and pets safe, through a four-part program: water deeply but infrequently; set mower blades for a lawn length of 3 inches or higher; use organic fertilizers; and weed naturally, by pulling them.

And if all else fails, it could still be a vintage year for dandelion wine.

Contact Camera Staff Writer Charlie Brennan at 303-473-1327 or