lay the vine down on the ground and cover a joint with moist soil. keep moist & it will root at this joint. do not cut the vine free from the mother vine until it has roots.

From my understanding after the harvest a healthy lower branch/vine is burried in a trench while still connected to the main vine, the following spring it is dug up and you can cut it into 4" sections making sure there is a root bud on each section. You now have rhizomes of identical genetics to the mother plant, they will also all be female. Check out the link for more info. what varieties of hops are you growing?

Here is a link that might be useful: Good information on Hop gardening