About the roses, Greenfly, do you mean during the flowering season, or do you mean over several years?
Iris - I'm assuming you are talking about bearded ones here - I had quite a few which were a bit overcrowded, and I separated them all up and replanted a few months after the flowering season. It's a couple of years ago now, and I'm not entirely sure exactly when I did it - possibly around August/September time, when the rhizomes were nice and fat and healthy, and they had time to re-establish themselves before winter.

I've never known about roses changing colour. maybe it is a shoot from the root stock. But so saying that I did have a customer who had one of those gaudy yellow and red stripey roses, which occasionally threw up yellow or red roses without markings.
Irises, rhizomes to be split or moved. should be done just after flowering. Cut out any old and diseased sections then replant, some folk cut the leaves down by half, some don't. Replant the rhizomes N to S, so they benefit from the sun. Allowing space for growth.

I always thought you should wait for about a couple of months after flowering, 2ndhand, to allow the rhizomes to build up some reserves. Is that not so?

Roses can revert. You have to remember that they've been bred from other roses! Sometimes you might also get suckers from below the graft points, and they must be removed by pulling them off, not cutting.

If you look back you will see this question about roses changing colour cropped up a couple of days ago if you want to have a look?
Some rose blooms can fade as they mature from yellow to cream or from deep pink to almost white.
Am I right in thinking the rose itself does not change colour as such Spritz? Its the root stock taking over if the graft is dead/damaged, which gives you quite a different rose.
In certain conditions grafting will not take at all and the root stock takes over, a relative in America says its the hot conditions that makes it impossible to grow grafted roses.

Yes, Denise. The flower from the rootstock will be a different colour from the plant's blooms.

I have a climbing rose which has cream flowers - but every year it produces a few pink blooms much to my surprise - certainly not from below the graft, either.

I remember my grandad growing baby masquerade,. The buds came out yellow and as the flower matured the petals changed to a deep red.
Thats amazing Spritz....I wonder why.....

No idea, Pam!

Some of the more newly bred roses don't retain their colour - peach turns pink the following year, for instance, so its reverting to one or other of its parents. And because, as Spritz rightly says, they're highly bred, sometimes you get genetic blips in the tissues.
But the more usual reason is that the grafted rose has died and now all the flowers are 'dog rose' type off the root stock, but its easy to tell with those - the flower form and colour is usually different, not to mention the growth habit and appearance of the stems.

Gattina, I have always followed the rule of moving once flowers had finished. I believe the RHS also advise it to be donewhen the flowers have faded.
I dig a shallow hole, build a mound in the centre and place the rhizome over the mound, then cover the roots with soil, thus leaving the rhizome on the surface. I have done this for years and usually it works. Although the last place I moved them too was not good, weed infested path, so they will get pride of place next week in one of my veg beds being turned over to plants that don't mind stoney soil. It's where i throw all my stones from the other veg beds.

Irises do seem to be pretty good-tempered plants, and not too difficult - I transferred my inherited ones to a very dry, sandy, weedy bank next to our drive, and they took a year to gather their strength, and then this year they flowered magnificently for the first time. Shame they've now all been dug up and eaten, the flowers and leaves all scattered around. Porcupines. :o(

Oooooooooooh. Don't have probs with porcupines. Infact I am virtually trouble free, except for the odd rabbit, usually dispatched, but too small for the pot.
Moles and Voles, I live with. Rats and mice are controlled.
Magpies and jackdaws pinch eggs and chicks occasionally, but that's life. Oh and the odd opportunist fox has had it's way with a few hens. But nothing more than that.
Couldn't cope with the rodents, vermin and critters you obviously have roaming about. not forgetting all those snakessssssssssssssssies.

We are really lucky - stories of snakes abound, but we have only ever seen one. We have dozens of cats, so the mouse and rat, mole and vole problem doesn't exist. Deer can be a problem, (red, fallow, roe AND muntjac)and very occasionally, wild boar. Strangely enough, no rabbits. We've seen one mangy fox, poor thing, obviously having a hard time. We used to get incredibly smelly polecats but they seem to have disappeared, like the fat dormice. The porcupines we have never had a problem with before, but there seems to have been a population explosion this year, and farmers round here are having a bad time with the damage they can do. (It's a major potato growing region). We can grow soft fruit without any kind of protection against the birds, again because of the cats. Buzzards keep the numbers of magpies down. Scorpions are tiny, rather pretty and don't hurt anyone. On a personal note, my biggest fear is the HUGE wasps that are beginning to appear again this year. Large cans of spray (sorry about the environment and all that) are placed strategically round the house, and a lot of flapping and screeching goes on if one appears. You can't miss 'em, they sound like Chinook helicopters on takeoff.

the buzzards don't mess with the magpies here. So no ally there. The rabbits have made another appearancem, but the dogs could be getting wabbit for tea. The polecats don't bother me much now that they cleared out my population of american bobwhite quails. And thankfully the muntjac problem we had before we moved didn't follow us. The scorpions here are harmless, not that we get them up here, nor do we get the slow worm, thank god to much like a snakey for my liking............ lizard or not, it still snakes about...................