About 2 years ago I cleared out quite a lot of cleavers from this tree (with lesser amounts in subsequent springs); hopefully the nutans has benefited from that!
Annuality of fb is the reason the present program is just to cut off and bag the seed-bearing heads, which is much faster and less strain than pulling out the whole plant, especially with the ground much drier. Tho I have a suspicion that some of the bigger plants with 4+ stems some of them > 5ft tall > one year old.
Avery, when we cut and bagged fleabane seed heads this time last year we got regrowth occurring with more flowering - admittedly in what turned out to be a wet year.
Two rounds of decapitation, or maybe even three, would still cover more area in less time than pulling them all out, and definitely less strain, in this area, under the current conditions (under the the power lines above the Bragg St park; wrist pains are definitely a limiting factor for me). But will definitely need to keep an eye on them.
my experience is that cut fleabane develops more flowering heads and it can look like a candelaber - reg the big Fb I cut the seed heads off and bag them, then I cut the whole plant close to the ground and dab it with 1:100 glypho mix. This method is much more gentle to the wrists than pulling (some of the 2m tall plants I can't pull anyway) however very laborious and I only do this in selected sites such as wildflower patches or where I have invested time and funds in the past 20 years...