I think the best time to prune in areas with freeze danger is in spring just before or as growth begins. I think this is too early in zone 7. I'd take cuttings for rooting 2-4 weeks before growth begins. Then they may need to be buried or stored in a cool place until rooting. It depends on whether you can control temperature or are reliant on nature, they need warmth to root rapidly. I'm not an expert on rooting grapes but have done it many times. Usually by just planting them where I wanted a vine, covering until spring, and then uncovering the top bud. This works but there are ways that result in much higher % takes. The key to rooting them is getting callus formation first. This works best at warm temperature, just the right moisture level, and rooting hormone. The cutting needs to be fully turgid but not wet. Some experts callus them in moist sand. This months Good Fruit Grower has an article on rooting grape cuttings. I've never used rooting hormone so that's not essential.

Cannas will regrow, no matter when you cut them back. But if you can wait til late fall, you can enjoy them all summer. It's really up to you. You're not going to hurt them by cutting them back at any time.

Thanks, Barrie. I'm going to enjoy the seed pods for another week or so, and have at it with the loppers. There are fewer new shoots than I thought, but I think I'll still go ahead. By the way, we were able to over-winter castor bean plants this year, after cutting them back in late January. They're so full and bush right now, they're starting to scare me!

if you don't prune knockouts they will eventually get way too tall and not have the shape you want. They should be trimmed like any other flowering shrub. I learned this from a very reliable source. If interested in the method go to the rose forum and read "Paul' Pruning Demo". I am at the beach and we pruned last weekend like our local rose society suggested. I would wait at least another week for you. I know it is supposed to get down to the 30's a couple of nights this week down here. The last frost date for your area is a good guide line.