I need some help please. How do I get rid of the Centaurea in my garden? It is taking over everywhere! I pull and pull and dig up, to no avail. I haven’t tried chemicals and don’t want to, but I will if that is the only way. Thankful for any suggestions.
Claire in Idaho
Claire, I haven’t had that problem in Connecticut. Sometimes when I’m trying to eradicate an aggressive plant I will dig up as much as possible. Then when it starts growing back I paint the leaves, using rubber gloves and a sponge paint brush, with glyphosate, better known as Roundup. For more of an organic approach you can try vinegar, but I’ve not tried painting on the vinegar. Eradication of something aggressive could take about three years and that’s being vigilant about the eradication. Hope this helps.
Sandy's Plants, Disease and Insect ID Blog 
I need some help please. How do I get rid of the Centaurea in my garden? It is taking over everywhere! I pull and pull and dig up, to no avail. I haven’t tried chemicals and don’t want to, but I will if that is the only way. Thankful for any suggestions.
Claire in Idaho
Claire, I haven’t had that problem in Connecticut. Sometimes when I’m trying to eradicate an aggressive plant I will dig up as much as possible. Then when it starts growing back I paint the leaves, using rubber gloves and a sponge paint brush, with glyphosate, better known as Roundup. For more of an organic approach you can try vinegar, but I’ve not tried painting on the vinegar. Eradication of something aggressive could take about three years and that’s being vigilant about the eradication. Hope this helps.