Published: Friday, August 27, 2010, 3:00 AM
Earlier this month, the city posted signs around the International Rose Test Garden in Washington Park announcing it had just sprayed pesticides and people should stay away.
When someone alerted me to this in an e-mail, I thought: What? Pesticides at the park? What else are they spraying? What about the grass my kids have been rolling around on?
I take such care not to use anything nasty on my lawn or garden (except a few granules of Sluggo once a year) but hadn’t thought about the park where we spend a significant amount of time.
So, I did some research and found out how huge the Portland park system is: 2.2 million square feet of developed shrub beds; six botanical gardens; three specialty rose gardens with more than 20,000 roses; and 1,360 acres of grass, including 365 athletic fields and five 18-hole golf courses. That’s a lot to weed by hand.
Back 30 years ago the city, like most others, routinely sprayed the grass with a broad-leaf herbicide, says John Reed, Portland Parks & Recreation integrated pest management program coordinator. This made the grass green and spongy — no clover, false dandelions or plantains. But it was expensive and a lot of chemicals.
Then in 1988 Portland moved to an “integrated pest management” approach, which is a fancy way of saying, in part, that the city looked at where it could lessen or stop chemicals it didn’t need while still maintaining beautiful parks.
Reed estimates the city uses less than 1 percent of the chemicals it once did fighting weeds in grass. Standing in Grant Park, typical of one of the city’s more highly used parks, Reed looked at the grass under his feet. It’s never sprayed anymore. Clover and some false dandelions grow alongside the grass, but it was green and kids were happily running on it a short way off.
“Really, what difference does it make?” he asks.
But the shrub beds are another matter. The city does hand-weed with help from the Alternative Community Service program, but Reed said it would be impossible to remove all the weeds this way from Grant Park’s 55,000 square feet of shrub beds. If a city parks person didn’t come by with a low-pressure backpack sprayer and squirt some Roundup on the beds a few times a year, weeds and blackberries would crowd out shrubs.
The city also sprays Roundup around the base of trees a couple of times a year, which is why they’re all ringed with a wide swath of dirt. Pointing to the knobby roots of a Douglas fir rising out of the soil — the tree’s root flare — Reed explained that mowers can’t scrape over these without seriously injuring the tree. So the city keeps the bases grass free. It also sprays the perimeter of the tennis and basketball courts to prevent grass from growing into the chain-link fences.
And nodding toward the athletic field at Grant Park, Reed explains that it uses a slow-release synthetic fertilizer formulated for turf. They also overseed and aerate; otherwise the field would just turn to mud from all the constant and heavy use.
What about insecticides?
The city does its best to avoid them.
It will use insecticides if, say, there’s a yellow jacket or wasp nest near a play structure, Reed says. If something has been sprayed, you will always know because the city posts caution signs and by law restricts the area until the chemical is dry.
Reed says he researches what pesticides to use by talking to university scientists and reading decisions by pesticide regulatory agencies. He isn’t just reading the label on the bottle.
Salmon-Safe, which looks at how land management processes relate to aquatic ecosystems, said this about Portland’s park management: “Pesticide use within Portland’s well-established IPM program is minimal and well-justified.”
Homeowners can learn to do more with less. Shareefah Hoover, a senior public affairs specialist with Metro, says homeowners who want a safe yard for children and pets should consult Metro’s “Grow Smart, Grow Safe” guide, which shows how to grow a beautiful lawn without fungicides, herbicides and insecticides.
Using chemicals on a park or yard is complex. Using a pesticide next to a creek is very different from using it 1,000 feet away.
The properties of different chemicals vary — some will readily move from where they’re sprayed and others are immobile until they break down. The average gardener isn’t going to research all that.
“It’s easier to use the message: Don’t use anything on your garden,” says Reed.
That’s my own approach.
So should parents take care to keep their small kids away from tree rings, shrubs and highly used athletic fields in the city’s parks? Reed says he would be more worried about dog feces than what he calls low-toxicity chemicals, since the amount in any given area is “so tiny, exposure shouldn’t create undue risk.”
Parks are public spaces and kids should always wash their hands after playing in one, whether chemicals were sprayed or not. But if you’re worried about pesticides in Portland parks, don’t think twice about running around or cartwheeling on that grass.