Dempster Sweetclover Eradication Program

Friends of Dempster Country Society feels that there is still the chance to prevent invasive Sweetclover (Melilotis albans) from spreading north along the Dempster Highway.

Members of the Friends of Dempster Country Society first noticed Sweetclover (Melilotus albans) on the Dempster Highway in the late 1990ís. It was then isolated to the first few kilometres of the Dempster Highway, adjacent to the Klondike Highway which is quite infested with Sweetclover in patches, including at the Dempsterís junction. Over the past 3 years, Society members have been keeping a close eye on the clover growing on the Dempster Highway. We have noticed it growing thicker every year near the beginning of the Highway (between km 0-5 in particular), and jumping further and further north. In the summer of 2007 it was found as far north as km 35 and this summer, in 2008 it has established second year growth at km 42. (Aside from a small patch of mature plants found at the Olgilvie River Bridge, Km 196, no clover is known from further north on the Highway except near communities in the NWT.) There is also a small infestation along the Historic Ditch Road which crosses the Dempster at km 6.4 and potentially there may be clover along the North Fork Road which crosses the Dempster at km 8. The Sweetclover infestation is relatively new and small on the Dempster. We hope to keep it from getting into the headwaters of the North Klondike and the pristine headwaters of the Blackstone and Olgilvie Rivers, a part of the Arctic Oceanís watershed, and from the Eagle River which flows into the Yukon River.

This summer, as a part of Botany Weekend 2008, we conducted the First Annual Dempster Sweetclover Pull. We managed to clear the Highway from around km 42 to km 9 of second year Sweetclover, excluding a patch near Bensen Creek (km 32), which was later found in a gravel pit just out of view of the Highway, and a small patch at km 21 which we overlooked. The clover was growing in patches and we pulled all the second year plants and as many of the first year ones as we could. As the seeds were not yet viable and the plants had only just begun to flower, we were able to leave the plants on the highway side, as advised by Toos Omtzigt, Manager of Environmental Affairs for Highways & Public Works, Yukon Government. The operation took all of 5 hours and included 9 major patches and a few very small ones.

We found that 2 year old Sweetclover can be spotted from a vehicle and it is possible to pull the entire plant, including the root. Sweetclover plants that had first germinated in 2007 and reached maturity this year, but not yet spread seed, were fairly easy to eradicate. Sweetclover patches whose plants had already matured and dropped their seeds were much harder, if not impossible to eradicate in one season. We were able to pull the mature (2 year old) plants, but the ground was covered in first year plants, and we could not pull them all. In these patches, we resorted to pulling all the mature Sweetclover and doing as much damage as we could to the immature clover. We mean to revisit these sites next June and pull any plants which reached maturity. With any luck, we will have eradicated most of the seedbank, although it is known that in some parts of the Yukon, first year Sweetclover is able to produce viable seed (this was observed at the large patch on the Ditch Road).

Next year we will revisit the sites we pulled this year and again pull the mature Sweetclover. We will also be sure to GPS and record the status of each site, which we did not do this year. We hope to enlist a Y2C2 crew to join us in the pull, and especially have them focus on the first 9 km of the highway, which will be more labour than the upper 30 km taken together. Overall, we feel that if we continue our efforts every year, we may be successful in stalling the spread of Sweetclover north on the Dempster Highway. Friends of Dempster Country Society is committed to continuing this work on an annual basis.

Thanks to the Klondike Highways Camp for allowing us to carry out this work.

Please contact us at: