Today 
These quick-growing plants are able to spread rapidly to create dense, thorny thickets of stems, which are able to root at the tips. The plants produce blackberry fruits, which contain seeds that can grow into new plants. The tough roots are able to grow again when the stems are cut down.
Solution
Organic
Cut back stems and dig out roots thoroughly. Pull out seedlings and young plants before they become established and spread.
Chemical
Cut back stems of established plants, and treat the regrowth in spring and summer with brushwood killer. Treat the foliage of seedlings and young plants with a systemic herbicide, which will kill the roots as well as the top growth.
