how late in the season can I transplant these two plants?
I live in Wisconsin
Help with Hosta' & Sedum's
I am in zone 6b and I plant as late as the first week in October. I'd say three weeks before average first frost date. Just a guess. Maybe someone in Wisc. will share their experience.
Hostas are hardy in WI and I think pretty much anywhere. You can transplant them anytime before the ground freezes. When I lived in the Milwaukee area, I would transplant them anytime from spring to summer to fall and they all survived and performed beautifully!
Likewise for Sedum I would say. Not finicky at all in my experience.
All plants need to be established before winter for a better chance to survive. Sedum leaves and stems are killed during frost. If not, established, the freezing and thawing that occurs even in winter will tear roots that are not "anchored " in the sol below. It is that action that kills plants over winter.
This is important mainly for Northern gardeners. I lost rooted cutting because I started them too late so were not established enough before winter.
I lived in zone 6b and I planted sedum in shade and sun and every year they return , but those in shade did much better and gave me beautiful blooms. I ordered some hostas from a catalog and did not know where to plant them, so i planted 2 in a large container in a sunny spot they did very well so I decided to keep them there.
My experiences here in zone 3 agree with Yadavgard's. Transplants can be done successfully at any time that the ground isn't frozen. If the root ball isn't disturbed, the plant won't even "know" it's been moved, or at least, there will be no visible reaction to it. Most commonly-grown sedum species are evergreen here and rock-solid hardy; yes, there are some tender species.
It's surprising to hear of sedums blooming better in shade than in sun though.