Slow growth after "knocking back"

I “knocked back” the second year hills in my most recently established hop yard during the third week of April, and they have yet to fully recover.  I was hoping to start training by the end of next week; however, I have a Cascade plant that appears to taking its good old time producing new shoots.  I do not believe that “knocking back” the hills caused this slow growth pattern.  I was careful not to cut the bines too close to the crown.  The new cultivars that I planted last fall are growing much slower than the one season cultivars that they replaced.  Is anyone else in the Mid-Atlantic region experiencing slower than normal growth?  I am willing to bet that the strange weather pattern that we have experienced this year has something to do with my hills growing slower than normal.