I would assume that at this time of the year the ground is still frozen. Even if it isn't, it isn't time yet -- the roots aren't going to start growing into soil that is too cold, so there is nothing to anchor them and they may get heaved out of the ground by freeze-thaw cycles, especially the shallow-rooted ones like iris. I'm not familiar with growing conditions in Colorado, but here in Michigan I don't start moving stuff around until late April earliest, later depending on the weather. We do plant bare-root woodies earlier but those don't start showing up in the nurseries until around April and mail-order usually doesn't ship here until that time, either.

Thanks, mxk. I guess I should have asked when/how soon I can transplant. As soon as i can dig, while plants are still dormant? Early spring when they are waking up and have green shoots? Or do I have to wait till late spring when there won’t be any more freezing? I understand that spring bloomers might not bloom if i transplant in the spring, but that’s a price I’m willing to pay. If I sow some larkspur seeds this spring, I should have color by June, I think.

Are there any nurseries up there (or nearby) that could help you with your specific situation? We were in Grand Lake (8300) and there was a fantastic nursery in Granby that didn’t sell anything that wouldn’t make it up at that altitude and had great advice!

it is ALWAYS better to transplant in dormancy.. no active growth to maintain.. for the week or two the roots arent pumping water ... last frost is irrelevant if still dormant...

just do it... live and learn ...

iris might be better moved after bloom ...

take a gob of soil with the plant.. put them in a plastic grocery bag.. and plant them when you get there .. watering them in.. might be an issue... much easier than potting them all up ..

ken

You want to wait until you can plant them in their new home. That means the ground isn't frozen. Whether the plant is dormant or not might depend on when the plant breaks dormancy --- early or late.

I transplant everything after it starts in the spring. I've transplanted lots of plants at the "wrong" time, like in the heat of summer, simply because that's when either they plant needed thinning (and the thinned out bits were planted elsewhere or because it was a gift from another gardener.

The trick to transplanting success is to water, water, water. Obviously, in the spring, there tends to be plenty of rain, making it less work to keep them well-watered.

Thanks, everyone. I think that i will get started in a few weeks. The cabin is in a sunny, protected spot and the soil is loose. I’m currently amending it with compost. So whenever I can get plants out of my garden with big clumps of soil, I will get start transferring; things go back and forth between warm sun and wet snow here in the spring. I have enough perennials that if the first round don’t do well, I can try again later. I’ve also ordered some seeds (blue flax, California poppies, and larkspur) that I think will do well, fingers crossed!