Aquatic Weed Guide for Benton County and Beyond

Ludwigia hexapetala inlet © A. Neill
A local inlet of the Willamette River infested with water primrose (Ludwigia hexapetala). © A. Neill

How many ornamental plants can you identify in your yard? How about native plants in your favorite park? Even people who know the majority of the plants growing in these locations may not be aware of the weeds threatening to take over our local waterways. Awareness of these aggressive invaders is a key step in protecting the habitats and recreational opportunities provided by the Willamette, the Marys, and the many other creeks, sloughs, and side channels in Benton County.

One particularly nasty invader is known as water-primrose (Ludwigia species). At least two invasive species of water-primrose have been found in the Willamette and its side channels. This escaped aquarium plant forms dense mats that crowd out the native plants and reduce wildlife habitat. You can help Benton SWCD and our partners manage aquatic infestations by learning which plants to look for and report. Our aquatic weed guide makes it easy for everyone, by focusing on a short list of twelve water weeds. Use the guide to learn which ones are here already and which ones we want you to report. Plus, it gives you an excuse to get on the river!

This waterproof, field-ready guide can be purchased from BSWCD for the low cost of $4. Stop by the office to pick up your copy today, or view the guide online.

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