Just leave it. You won't get many berries this season, and since blackberries only produce on 1 year old wood, you might as well leave what growth you do have. I got maybe 15 berries from my 6 newly planted blackberry plants last year and I think I got 2 from the boysenberry I planted, so don't expect too much.

You'll get a decent crop next year and then they'll really start producing the following year.

Good luck.

Brandon:

Just to get the terminology straight, the suckers that you see will become your primocanes. The stick in the middle is last year's primocane, but now a floricane. It doesn't matter whether you clip it or not, since it will not affect new growth. The future in in the sprouts that you see.

Don Yellman, Great Falls, VA