Grow like a bad weed don't they? There may be others on here with more expertise, but I've grown 4 different types beginning 4 years ago, and took a mean shovel to them to spread them out and replant last fall. Initially I've let it go with no trimming, but now I plan on sticking with the thickest one once the longest reaches a foot or so, maybe laying down some plastic and spiking a shovel around each crown to about a 1-1.5 foot radius to slow their spread. I threw out a lot of hops last year because I couldn't pull them apart--Cascade, Nugget, Centennial and Mt. Hood. Be sure the varieties have plenty of space between them, i.e. several feet, otherwise they will find each other and you'll have this beautiful vine wall with no separation.