Sauk-Suiattle Indian Tribe 2013 Knotweed Eradication Efforts Andrew W. McDonnell Natural Resources Field Coordinator Sauk-Suiattle Indian Tribe

Clusters of knotweed at the watershed level. Darrington: People Prairie: Machinery Middle Sauk: Not so much knotweed…Pretty swift. Lower Sauk: Fans out, a lot of sidechannel and backwater habitats. This slows down the transport of water, sediment, and it turns out, knotweed.

2013 – 13.28 gallons concentrated glyphosate Herbicide – Imazapyr 1% 118 gallons in solution 1.18 gallons concentrated 2011 Herbicide – Imazapyr 1% 470 gallons in solution 4.70 gallons concentrated 2012 2013 Herbicide – Imazapyr 1% 298 gallons in solution 2.98 gallons concentrated As we visit more historical patches, and discover new ones, we tend to spray more herbicide to control the spread. Read off. Sprayed less Imazapyr this year despite visiting more patches than in 2012. Patch sizes are reducing! 2013 – 13.28 gallons concentrated glyphosate

7% 40% 33% 17% 3%

2 yrs of treatments Two years of consecutive treatments resulted in 71% of new patches identified in 2011 to be dead.

2 yrs of treatments 1 yrs of treatments Next add 85% +- 7% reduction in size. Fix: Remove Red Bar.

2012 Field Season 2013 Field Season Priority Areas for 2013. Status following 2012 treatments Status as of 2013 (Effectiveness of those treatments)

4 acres

4 acres How did we treat this? Took about a day to bend Treated with Imazapyr and glyphosate 3 days of treatments Interesting observation: knotweed seemed to be growing mostly in and around old stumps, so it actually made paths for us to navigate though while spraying.

Snohomish County Noxious Weed Control Board Wild & Scenic River Tours