Land Plants - non-native

Knapweed (species unknown) (Centaurea) on Aug 16, 2022

Submitter does not have a specimen

Description of specimen

Purple flower, slender alternate leaves.spots under flower.

Commentary

Hi Delani,
Thanks for your report!
This looks like meadow knapweed, one of several invasive knapweeds in our area. I will bring this infestation to the attention of the folks at Keizer Parks. Check out BMPs from King County to learn more about control of meadow knapweed: https://your.kingcounty.gov/dnrp/library/water-and-land/weeds/BMPs/Meadow-Knapweed-control.pdf.

Thanks for your report!
-Sarah Hamilton
Native & Invasive Plant Specialist
Marion SWCD

Sarah Hamilton
April 25, 2023, 3:20 a.m.

Resources

There are many non-native knapweeds present in Oregon, and their identification can be difficult. Some species hybridize. Here is one resource for identification: Identification of starthistles and knapweeds in the Pacific Northwest, but there may be more recent descriptions available.

Location

Dirt trail along the river.

Expert Reviewer

Sarah Hamilton
Marion Soil & Water Conservation District

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