Can girdling kill Canadian Thistle?

I plan to experiment with girdling the stems of Canadian Thistle on our property using sandpaper or other materials. The idea is to remove a section of phloem around the stem, near the base, to interrupt transport of sugars from leaves to the roots. This will also keep the leaves in place to continue transpiring and pulling water/nutrients out of the roots, essentially starving the roots while draining them too. This approach is being considered because with Canadian Thistle, the roots are the hardest part to kill, and I'm interested in mechanical control methods vs chemical.

Does anyone know if the phloem/xylem structure of a hollow stem like that of the thistle will make this possible? I'd like to use food coloring to mark and observe these structures in a cross section, but have yet to perform that experiment. I'm not sure if the xylem of a thistle stem is just the hollow center (pith), or if there's an actual series of cells near the hollow. If anyone's interested, I'll post images of the coloring experiment soon.

Concerns: girdling too early in the season could lead to more numerous flowers/seeds, as is the goal with girdling apple trees. Also, will thistles be too good at regenerating phloem?  Is it possible to damage the phloem and keep the plant standing?

Other thoughts? Advice? Resources?

Thanks!
df