John here are my recommendations. Maintain current height for now until it goes dormant for winter rest. Then next spring with you see signs it is starting to turn green, scalp it down to 1 inch and bag all the debris. I will warn you it will look like crap with nothing but stems and twigs. As soon as you see it starting to recover and green up a bit after scalping, apply your first of 3 yearly fertilizer applications. Be sure to water the fertilizer in. Then maintain the lawn at 1-1/2 to 2 inches with a rotary mower with a good sharp blade. Zoysia is a very tough grass and hard on lawn mower blades so keep the blade sharp. Otherwise you will just tear the grass and it will look brown on the tips and spoil the color, not to mention open it up for pest and disease issues. If you use a reel mower maintain at 3/4 to 1-1/2 inches with sharp blades. Lastly fertilize only 3 times per season spaced 8 to 10 weeks apart. DO NOT over fertilize Zoysia. Good luck and don't forget to check in next year and let us know how it went.

I whack my type IIIs off at six inches because I prefer new growth up from the ground rather than from last years vines but most won't cut that severely. It is up to you. You can start at the ground and go up to the closest set of buds and cut just above them.

Think you're in the wrong forum. The forum for ornamental grasses is at http://forums.gardenweb.com/forums/grasses/ Even so, that's an ornamental grass, perhaps a Miscanthus. Many of the grasses are cut down to 4 or 6 inches every year. Depending upon where you live, it can be best to wait until the weather begins to warm in the spring.

They're already producing pumpkins and NOW you want to move them? Do you realize how deep and extensive the root system is by now? Sure, you can cut them back on top and they'll probably regrow, but you try to dig them out of the bed and they'll lose a large fraction of their roots. The damage you'll inflict is down below more than up above. Sounds like a losing proposition.