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The City of Portland, Oregon

Portland Parks & Recreation

Healthy Parks, Healthy Portland

Phone: 503-823-7529

1120 SW Fifth Avenue, Portland, OR 97204

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What is IPM?
IPM first determines if a pest needs to be managed, and if so, when, where, and how best to do it. Key elements of an IPM program are information gathering, well-informed decision making, and monitoring of results. IPM uses many strategies to achieve its goals, combining policies, cultural practices, mechanical means, and biological and pesticidal methods. The IPM process ensures that the most effective, low-risk methods and materials are used to manage pests. Here are a few examples of IPM in Portland parks:

  • Mulching planting beds to prevent new weeds.
  • Mowing high grass and brush to reduce weed seed crops in low maintenance areas.
  • Pruning plants to increase air circulation helping to suppress some diseases.
  • Correct fertilization to encourage plant health and resistance to pests.
  • Using plants with natural resistance to pests.
  • Aerating and overseeding turf to encourage healthy grass.
  • Applying carefully selected herbicides to control weeds before they can seed.

Why do we need IPM in our parks?
IPM makes it possible to responsibly care for the 250 parks and recreational sites in our system, totaling over 11,000 acres. Portland's parks are a multi-billion dollar asset and include over 2.2 million square feet of developed shrub beds, three major rose gardens, five championship golf courses, and thousands of acres of natural area. Keeping our plantings healthy, our landscapes well maintained, and our natural areas in ecological balance requires an IPM program. IPM is especially important for PP&R since we have so many acres to care for, a limited number of people to do so, and high standards of safety and environmental protection.

Who manages pests in Portland parks?
The cornerstone of our IPM program is our trained staff of knowledgeable horticulturists, ecologists, technicians, and specialists. Their understanding of plant and landscape needs makes possible the individual determinations needed for IPM in our many park sites. Our policies require that all personnel who apply pesticides of any kind be required to maintain a state administered Oregon Public Pesticide Applicators license. To keep this license they are also required to attend continuing training and education where they learn about the latest IPM and pest management techniques and materials. Our licensing requirements exceed state and federal standards. PP&R is committed to this higher level of training for our applicators. PP&R's IPM Coordinator develops and refines the program, and ensures that regulatory requirements are met. The coordinator also researches IPM science, develops pest management strategies, trains staff, and communicates with the public and other bureaus.

On what are IPM decisions based?
When developing and updating our program, we rely on the best expert scientific opinions to inform us about the materials and methods we use. Assessments from agencies such as the Environmental Protection Agency and the World Health Organization are starting points for us, as are state universities. University extension scientists provide much useful information about the latest IPM research. We turn to these recognized experts for trustworthy science-based information. We also follow the latest pertinent studies in this process. By basing our decisions on these authoritative sources, we can arrive at the best solutions within our IPM framework.

How will I know if PP&R applicators are applying pesticides in a park?
PP&R understands that park users may want to be made aware of these treatments, and we have a notification system that goes beyond federal and state requirements. When an area is being treated with any pesticide, the applicator will place signs that include basic information such as the name of the product being used, what is being treated, directions for park visitors, and contact phone numbers to get additional information. Calling PP&R makes it easy to get additional accurate information about the pest problem and other pertinent details.

Is household vinegar an effective alternative to kill weeds in the parks system?
No. Household vinegar (with 5% acetic acid) does not kill the roots or below ground parts of a plant. Further, it is most effective at controlling small, immature plants. Larger weeds and perennial weeds may wilt and discolor after spraying, but may begin to re-grow a week or so later since root systems are not killed. Unless you can apply early and often it will not kill weeds. PP&R oversees over 11,000 acres and unfortunately, we are not always able to target weeds as soon as they germinate. Most importantly, it is illegal for the Bureau to use a product as an herbicide or pesticide if that is not its intended purpose per the federal Environmental Protection Agency (EPA). To summarize, household vinegar may be an effective temporary tool for a homeowner in a small area of newly established weeds; but it is no more effective than mowing, and less effective than mulching or hand pulling. And it is not a feasible option for Portland Parks & Recreation to utilize.