I'm new to gardening, and surely I'm making a lot of mistakes, but I'm pretty freely moving stuff around and having some luck. Here's what I've moved so far:

spiderwort: moved some established plants from dry sun to moist shade just a few weeks ago. The new growth is shooting out of the ground.

bleeding heart (or something related to it): moved this from moist shade to moist shade a few weeks ago. Even though I lopped off some big roots in the process, the new growth is absolutely shooting up.

lupine seedlings: transplanted from dry sun to dry sun last week. They seem happy.

established lupine: supposedly these don't transplant well, but I moved about a gallon of dirt with each of three plants last week from dry full sun to dry full sun, and so far the new growth looks unwilted.

skunk cabbage: my half-hearted attempts at re-establishing a couple of these when I dug a pond a few weeks ago have failed. The roots run much too deep to dig up without harming them.

jack-in-the-pulpit: I tried relocating some of these late last summer. They were extremely fragile and prone to wilt after transplanting. I don't know yet if they have survived the winter.

wild violets: these transplant with ease even while in bloom.

irises (I don't know if they are native or not): I transplanted these about a month ago, just as the new growth was starting to show. They are growing nicely so far.

Virginia creeper seedlings: tried moving these last summer in the heat into a sunny dry location. I think I killed them.

yarrow: easy to move. The stolons I transplanted a few weeks ago are looking very lively, and the ones I transplanted in the heat of last summer flowered for me.

I move things around alot for the same reason. I usually have good results as long as it is not too hot out. I have moved them in the summer, but it is harder for the plants to recover. I moved the following last year (that I remember): Jack in the pulpit, cordyalis, gentian, differents ferns, Ironweed, Culver's Root, Lobelia, Actea, Solomon's seal, Asters, and Goldenrod.

Rhonda

I have moved coneflowers several times. No problems. I have also moved asters, goldenrods, blazing stars and little bluestem. Most of the stuff I moved had only been established for one year, so I don't know how hard it would be to move more established plants. I know that taproot plants are very hard to relocate. I have only moved my plants in the spring and would say that is the best time. Fall, also could be a good time to move plants.

Keith

Bob64,
When I move spring ephemeral plants like Bloodroot (or trilliums, Jack-in-the-pulpit, mayapple - anything that seems sort of succulent and disappears in mid summer) I try to wait until the plant is going dormant in late summer, or move it very early in spring as soon as growth appears so i can find it. This type of plant seems prone to wilting and going dormant if transplanted during the spring and early summer growing season, so waiting until it has had a full season of growth to store energy in the roots seems to make sense. i have had a good deal of success with either very early or late transplanting. You could probably transplant these in fall too, but you'd have to find them and not destroy the roots while digging around for them.

I transplant a lot of native plants in the spring including and especially bloodroot because I have so much of it. I provide plants for two plant sales in early-mid-May and pot up dozens and dozens of all kinds of plants. If done right they hardly know they have been moved.

I move whenever I want to and happen to have the time to do it....and have always had good luck. Could it be that natives can maybe take more stresses than otherwise 'cultivated' plants? Last spring and summer, I moved several things from a friend's woods to mine...not even labeling what all it was and where. I have had numerous surprises this spring already of things that are coming up here and there.

Sue

I've been itching to do some transplanting/shuffling, but it was too dry 'round these parts. Thankfully we got some some rain recently - a perfect time to do this sorta thing.
My major volunteers - virginia knotweed (Polygonum virginianum), viola (love the wood violets), deer tongue Grass (Panicum clandestinum) and enchanters nightshade (Circaea lutetiana (Circaea quadrisulcata) transplant very easily - especially when small in spring time.
I'll also be transplanting my asters (Eurybia divaricata (Aster divaricatus) as well.
Some echinacea were transplanted to another location, as was some lobelia cardinalis.
I'm waiting to see if any of the other plantings from the last few years (ironweed, joe pye, butterfly weed) have multiplied so I can bring those to other parts of the garden.

Last year I moved some solomons seal and that is doing splendidly in it's new location.

I'm not always gentle with plants - those that require special treatment (anything other than watering until established) seldom work for me. I'm not very good with seed either.

shuffling is one of my favorite things to do.
especially after (or during) a nice rain.

I need to append what I wrote about skunk cabbage. The ones I had half-heartedly moved did finally come up, and look none the worse for wear. I also tried carefully potting some up, and a week later they still look quite satisfied in their new pots.

Update: The bloodroots that I moved are doing well in their new home.

I moved some too and they were fine for a day ... until the deer ate them. Dang it! But they did put out a few more leaves after that (and I was surprised to see that).

I dug up some up my rampant growers to share with friends yesterday: a spreading Tiarella, netted chain fern, Georgia aster, and mountain mint (Pycnanthemum sp.).

That's interesting Esh. Blood roots are one of the few plants I have that no animal seems to nibble on. The deer do eat saplings, rhodos, azaleas, various flowers, shrubs, and just about everything else but rocks but they seem to leave alone the blood roots, may apples and spice bush. Do southern deer have different tastes than northern deer? FYI, someone at a local nature preserve said that some deer have been observed eating garlic mustard (apparently after they already ate everything else).

some deer have been observed eating garlic mustard

Someone should clone those deer!

Last year when I moved from a wooded yard in PA, I invited friends to come take samples of the different natives that were well-established. I haven't heard back how their selections have done, but my aconites, bloodroot, assorted violets, native bleeding hearts, and twinleaf have all shown up this spring in Baltimore.

My hope was -- since there was no guarantee the next owner of the property would be as devoted as I was to destroying garlic mustard -- that the dispersing plants to multiple gardens was the best chance of ensuring _some_ of the stock survived.