Cut it to the ground...it will come back fresh and new. or if you don't want it al all, dig it out.
Linda C

For digging out ancient and woody plants you may need one or more of the following - a spading fork with a sturdy handle and strong tines; a mattock; a pick axe; a pry bar.

You can reduce the top by using loppers and/or a pruning saw or swedish bow saw. Something with sharp teeth and a good set for clearing green wood from the cut. A carpenter's rip saw doesn't usually have enough set for this sort of work. A chain saw is not recommended, though you could use a brush cutter...

A splitting axe can be useful for breaking into a clump but be prepared for the time afterwards to restore the edge if your soil is stony. ;-(

A spade or long-handled shovel with a keen cutting edge can also be useful for chopping through the roots and prising up the clump.

If you have clay soil - try to get the job done while the soil is still workable and not summer hardbake.

If you can't get to all the plants this season be sure to cut off the flower heads to reduce the number of seeds.

Expect another crop for a few more years - but they should be easier to remove, being young and juicy. Safe to compost so long as they're out before seed time.

Post it on freecycle: "free for digging"!