Bud Blancher Knapweed

Day 292: If you're out walking and happen to see pretty little purple flowers which don't exactly fit the description of "thistle" because they're not thorny, or that remind you of Ragged Robin (if you have those in your area) or Bachelor's Buttons, step up and take a closer look. Chances are, it will be one of several species or hybrids in the Knapweed family, and a rapidly spreading invasive in many parts of North America. Even as a private citizen (as opposed to someone affiliated with an organization like the Invasive Plant Council), you can report your sighting on-line through EDDMapS at https://www.eddmaps.org/ and for those of you who have smarter phones than mine, there are apps to make the process easier. EDDMapS stands for "Early Detection and Distribution Mapping System." It is part of the University of Georgia's Center for Invasive Species and Ecosystem Health. Per their web page, "Early detection of new invasive species infestations and rapid, coordinated responses are needed to eradicate or contain invasions before they become too widespread and control becomes technically and financially impossible."

Knapweed is a growing concern here in the Pacific Northwest (unintended but appropriate pun, there). It can establish a monoculture in a very short period of time, and is sufficiently virulent to even give Scotch Broom a run for the money. Although many city, county and state agencies try to stay on top of it in their parks and on their trails, it goes without treatment on adjacent private properties. If you find it in a location where you can legally remove it, bag the heads before cutting, being careful not to shake loose any developing seed. Dislodged seed may continue to develop if it drops to the ground. Dispose of the bagged seed heads by placing them in your household garbage. Do not attempt to compost them; the temperature in a compost heap is not sufficient to destroy them. In worst-case scenarios, chemical treatment is recommended. Check with your local weed board to find out which chemicals can be used in your area.

Invasive Alert - Meadow Knapweed

Day 261: Recently, the Invasive Plant Council asked me to lead an introductory walk for new members, and after some discussion of potential locations, we settled on Eatonville's Bud Blancher Trail with the option of continuing into Pack Forest. Since I walk Bud Blancher quite frequently in the winter months as part of the Park's fitness challenge, I expected that the trainees would find very little (if anything) to report. I figured we'd practice by taking GPS readings on ivy, holly and Stinky Bob (Herb Robert). Since these species are so prevalent, we don't include them in our surveys unless there's a good possibility that they can be controlled easily by the land manager for the area, except to make a note in our reports that they are present.

Due to the distance from urban centers, I only had one trainee sign up for my walk: a young botanist/teacher from Puyallup. I arrived on site early, and while I was waiting for him to arrive, I noticed something purple growing at the top of the berm beside the trail. It was obviously not a thistle, so I climbed up for a better look. Aaaaggghhhh! Meadow Knapweed! There were several instances of it along a little side-trail on city property, so when Ian arrived, I announced that we could start the day off with a "positive," i.e., we'd found an infestation. As we walked down the first half-mile of the trail, we found several more occurrences, including one patch about 40' in diameter.

Meadow Knapweed (Centaurea debeauxii) is a hybrid of two other species of knapweed, Centaurea jacea x nigra (Brown Knapweed and Black Knapweed). There are eight species on the list of invasives in Washington. They are best controlled by using a combination of techniques to prevent their spread. Pulling is often not enough and must be followed by chemical treatment. However, if you see knapweeds on your property, pull them from the base and bag them to prevent the heads from going to seed.