I want to get rid of one of my blackberry plants (a Brazos that's been in the ground 3 years). I have some Roundup and am thinking of using it on the new canes. The berries started ripening here a few weeks ago, but between birds, thrips etc I didn't get to enjoy them much.

Then should I dig up the main roots after some time? I've already stopped giving it water. As for the suckers coming up out of the ground, can I spray those too after more leaves appear, then dig them up (as much as is practical) after some time?

When I first noticed what looked like thrips, I tossed several berries over the back fence into an open field. Later I tossed some of the overripe berries that were crawling with other bugs. Is it OK to toss the berries like that, or are there seeds that may start new plants? (Also does that allow thrips to multiply?) The field gets mowed a couple times a year, and I go back there periodically to check on things. Thanks.