Giant perennial weed
For the last few summers, a large, deeply-rooted cluster of giant weeds has taken up residence around the base of my 30 foot pine tree in my backyard. They grow to over 6' and seem to be multiplying. I've sprayed a couple of times this season and have tried digging them up in the past, but reading about the Giant Hogweed made me wonder if I should be even attempting eradication on my own. Hopefully the attached image will help identify the beast, and then you can let me know how to proceed from there.
This is pokeweed, a native plant that produces purple berries in the late summer/fall that birds relish and spread. If this is a natural area, it would be good to leave it. Otherwise...
It has a huge tuber-like root that stores a lot of carbs. If you don't dig up the whole root, it can regenerate from a piece. There is more than one way to tackle this.
1. Exhaust the root system: just keep cutting new shoots back as soon as they appear until the roots don't have enough energy to produce new shoots.
2. Use a systemic herbicide that will travel down and kill the root. Glyphosate is the ingredient to look for on the herbicide label. Triclopy may also work. This is a perennial weed and when you've got a hard-to-kill perennial weed like this, you often get a better result with the spray when you spray in late summer/early fall when the plant is pulling resources down to its root system. It will pull the herbicide down more efficiently then. Wait two weeks and spray a second time.