Not sure how they can get much bigger, they were monsters and some of them were even larger than in the picture above. The 2nd year plant yielded me nearly 2 lbs dried before I gave the rest of the plant away and there was probably another 1 lb+ left on the plant. It was a monster.
Here's a pic of it at midway through the season. Cascade on left, 1st year Centennial in the middle and 1st year Columbus on the right.