I just discovered your website today as I was researching ways to conquer yellow hawkweed. We have a place in a remote area of the West Kootenays in British Columbia and both Yellow & Orange hawkweed has been spreading along the roadsides for the past few years; including along the ATV, logging & forest service roads that lead to the high alpine & mountain caribou habitat.
My personal 'fight' with the hawkweed is along the roadside adjacent to our property. I've managed to remove 90% of the tansy, 80% of the white, yellow & pink clover, 80% of the dandelions, 50% of the oxeye daisys, and 50% of the non-native buttercups. Every few years BC hydro hires a contractor to 'slash-cut' the roadsides of whatever shrubs & small trees are threatening to grow up under the power lines. 2 years ago their slash job was drastic, cutting all the native willows & thimbleberry bushes to about 6" from the ground. This has had both negative & positive impacts. Where there had been an almost inpenetrable mass of willows & thimbleberry; there are now dogwoods, dwarf woodland roses, bunchberry, strawberry, ferns, bog orchids, pink daisies, fireweed, asters, pink wintergreen, violets, goatsbeard (Aruncus sp), and this summer I even found a Calypso orchid. Of course the willows & thimbleberry are growing back, I am now keeping them under control to allow for greater diversity; and hopefully to prevent another slash next time around - in other words I am hoping it will be obvious that a slash is not necessary.
On the negative side the roadside weeds are now trying to encroach down the rather steep bank where I'm valiantly trying to promote the native wildflowers. As our time there until recently had been limited to spring & fall holidays, I did my best with manual removal of the weeds. However last fall I ran out of time at the far end of our roadside & there was about 4' of roadside that had a few scattered yellow hawkweeds left as well as few dandelions, daisies, buttercups, etc. (no tansy though). This spring those few scattered hawkweeds had become a solid mat of hawkweed, covering about 20 square feet. Valiantly I pulled up all of this mat - roots, runners, rhizomes & all - not realizing how much seed was in the ground! (By the way the root system is shallow & fibrous - it sometimes comes up as you pull on the flower stem). After weeding the rest of the roadside & roadside bank we then set up a sprinkler system on a timer hoping that this would favour the natives. I now have another almost solid mass of yellow hawkweed covering an even larger area - close to 100 sq. feet. The rest of the roadsie & bank is doing wonderfully & the natives are winning - but for how long?? The Hawkweed army approaches!!! I can't mow - this is not a lawn - I have no lawn actually. Other than the building site we have woodland & a large moss bed where I have been planting native wildflowers (and no, I don't dig up native wildflowers).
I realize part of my problem is poor soil - it is a roadside. Any suggestions?? If & when I manage to conquer our roadside my goal is to tackle the surrounding roadside areas - hopefully with the support (if not the help) of my neighbours - some of whom like to have a little hawkweed & tansy growing in their garden!! Yes I'm trying very hard to educate them on invasive plant species but it is an uphill battle.
