In general, perennials are best divided either early spring as they are sprouting or early fall and then mulched so that the soil stays warm enough for roots to grow well for a while and to prevent frost heaving during winter.

However, some things, like that grass, which I have heard called ribbon grass, and Siberian iris are pretty tough and can be dug up and transplanted just about any time. Just give them some shade (I tend to use outdoor chairs for larger plants or wooden shingles standing on end for shorter things) for a bit and water them in very well and continue to water when the soil starts to feel dry a half inch or so down until they seem well established. I would go ahead and dig up all the ribbon grass you can and then if you want some that will stay put, replant it in something that will contain it. I have some in a clay chimney tile and another clump in a half whiskey barrel. It's hardy enough to survive my winters in an above ground container with no protection, so it will be fine for you. Alternatively, you can take a very large plastic pot (I use nursery pots that trees have come in) and cut the bottom out, sink it in the garden and plant whatever is too aggressive in it, and then just watch to see that my aggressive plant doesn't wander over the edge of the pot. Then in the area where you took out the ribbon grass, to keep any remaining roots of the grass from getting re-established, either mow the area often, or cover it with several layers of overlapping heavy cardboard covered with mulch or cover the area with black plastic with the edges weighted down. If you are in a real hurry, you can use Roundup/Glysophate on sprouts, but I tend to not use manmade herbicides if I don't need to. Once you are sure all the ribbon grass is dead, you can replant the area.

I think your white foliaged plant is an ornamental willow, Salix integra 'Hakuro Nishiki'. Often in early spring the previous year's growth is cut back to keep it small and make the plant put out lots of those new white-foliaged branches which will have reddish winter bark. I don't know if you can do that at this time of year as I don't grow this plant. Yours is grown as a standard. See the link for an explanation of what a standard is and how to care for Hakuro Nishiki.

Here is a link that might be useful: Salix integra 'Hakuro Nishiki'

awesome link - thanks!

Where are you? I'd come and help you dig out the grass. Now is a good time to divide the iris since they just bloomed a couple of weeks ago. I just did mine and got tons too. I am going to fill a new formal bed in my front garden with them. Just hoping there is enough sun out there. Since they are free I figure it's worth a try. They are so beautiful when they bloom and I love the foliage the rest of the time.

I am in Andover, MA. If you're close enough you're welcomed to come and take a bunch.

Hey Froofy, I think your email is disabled. I'd like to send you a message.

i emailed you, i think. let me know if it doesn't go thru.

I'll try to figure out how to enable email right now.

But I'm very close to Andover center. Anytime, really. I'm mostly around all day all summer. And am in no rush to clean up this bed. The ornamental grass can sit there waiting for you till fall... or next spring even!

Let's plan on fall. I am in the Framingham area.

I just want to share a vision I saw the other day. I drove down a street that I hadn't driven down in awhile. A homeowner had planted this ribbon grass in his front yard, and it had expanded to cover about a 20 ft swath. It was scary! I have always heard that ribbon grass can really get out of control and now I see just how much. I would be careful of actually moving that to a new location. Maybe you would want to dig some of it out and dispose of it properly, so it can't root somewhere else either. If you really enjoy the plant, maybe you want to keep some of it and watch how it performs to make sure you really want it in multiple locations. Just from my own point of view, the number one job I hate in the garden, is fighting plants that get out of control, so I try to be pro active about that.

Yes, ribbon grass is one of those plants you either want to fill a large space or you plant it in a buried container of some sort and watch it bery carefully. Another way to control it is to plant it in the shade. That slows it down quite a bit. I am thinking of experimenting with both strategies in my garden.

it was cute in the winter when it was only about 6 inches tall. Now it's about a foot or more tall.

I have no idea where to move it in my yard. I guess I can't say I really care for it.

I like the container idea to keep it small.

Did you ever get information on dividing your iris?

irises - yes. I've got some ideas to move some - but again there are a ton. More than I can think of places for. There will surely be a bunch here when/if you come for some ribbon grass.

froofy - if you want to e-mail me thru my profile, I'd be happy to come take some of those siberian irises off your hands. FWIW - with siberica, I usually dig out the whole clump, then I use a hatched or my pruning saw to break them down into manageable clumps.

Great Froofy. I would be happy to help you divide them in the fall. I just did this for a friend of mine and we wound up with about 15 large plants out of two clumps. Let's touch base in September or so.