If it is a woody stem bush then i am not sure if this will work. If it is a green stem bush then I am sure this will work: vinegar! Pour a whole gallon of vinegar on an area of thorny bushes, soak the leaves and the plant, and by the next day it will be dry and shriveled and will not grow back! i had thorns/thistles last year that would not die. I tried stuff I bought from the store, all kind of things and they just kept coming back, but a good amount of vinegar and they are gone. Hope it works!
By
01/07/2011
I'm a little confused by your question. Why can't you just cut them down?