Since so many people are planting this year I thought I'd post a picture of the rope the hop yards use. As you can see, this isn't a simple twine. More like 1/4" rope and rough. It's made from coconut husks and good for several years. Since it's a rope, it won't unravel the way twine will. I first used this two years ago and this year, I only had to replace one of the lines out of eight.
Twine on the left, Coir yarn on the right.
Twine on the left, Coir yarn on the right.