This observations is for zone 4/5 gardners. Up until winter of 2007/2008 I never successfully overwintered miscanthus cultivars either in in pots or that were divided and re-planted in the fall. The only success I had was last winter when I over wintered 4 miscanthus, 2 fargesia bamboo plus other assorted plants in my basement escape window well. Everything survived beautifully. (We have no children and use our basememnt only for storage so this was not a fire trap). My suggestion for northern gardners who want to transplant grasses in fall is do it ASAP, mulch with shredded leaves and cover the crown with a big pot weighted down with stones or brick. Using this method I have overwintered tender plants like snapdragons.

In my experience, Zinnia seedlings are very easy to transplant. I direct sow a swath of the tall Zinnias every year, sow the seeds about 3-4 inches apart and there are always too many. I've had great success thinning them out and moving extras to a new location, even when they are up to 6-12 inches tall. Not sure about the shorter Zinnias. As for most WS seedlings I usually wait until they're at least 1-2 inches tall to plant out from the containers. They are a little easier to establish with more roots. I plant them out in small groupings, and usually separate out the seedlings. But HOS works for a lot of seedlings too. I have gardens all over the yard, and once plant out time comes, the seedlings are all over the place. I often have to do a lot of watering to make sure the babies get established, and often slugs are a problem too, because they love seedlings! Transplanting them a little larger might help them survive.

Hard to tell what grass you are referring to. Pennisetum Rubrum? Maybe a Millet grass? My guess is Rubrum (Purple Fountain Grass). Go ahead now and move/divide. Use a loose, well-draining soil. You don't really need to feed, but if you want to add something, make it a slower release fertilizer or some organic fertilizer.

Weed B Gon...well, I'd test that theory before using it, although if the previous owner got away with it, it should be OK. There are plenty of species of grass you can't use it on. Still, I'm not willing to give it a green light without knowing the exact species of ornamental and seeing that species on the label as being OK and wouldn't recommend using it without testing unless you have that assurance. RoundUp will kill any green plant it touches that hasn't had a certain gene sequence inserted. Yours are not immune. Don't use it. With my Zebra grass, a lot of manual effort is required. It's often best to inspect weekly and take care of problems as they develop. That little tree is easier to remove as a tiny seedling rather than wait until it's a sapling. Annoying, sure. But that's true of most problems, I guess. Mulching will certainly help, as will application of Preen early in the season next year (although take a look at the weeds you actually get and match the correct pre-emergent to the correct weeds. I have been...well, less than impressed with Preen, let's just say, due to my weed profile). Reapply said pre-emergent when the shield runs out, which will be dependent on the pre-m and the dose used (my Prodiamine lasts 9 months, but that's the dose I use--and it's the maximum for the year). Like any other summer-growing grass, these also benefit from a moderate feeding on-schedule. You can look up care online, or just ask and we'll outline the care and feeding strategy for you. This is already getting kind of long.