I have some Sterling hops that grow very well but don't seem to produce many hop cones. First year it grew to about 15 ft with no cones, Second year 20 ft, no cones. Third year (this season) it's over 25 ft tall, lots of vines, nice big green leaves, very healthy plant but probably only 20 - 30 hop cones. In previous research I found articles that indicated Sterling hops should start producing in 3 years. Anybody have suggestions? Should I be trimming some of the vines so that only 2-3 are allowed to grow? It produced lots of tall vines. Like I say a very healthy plant, just no hops.