Try to get a solid soil ball without disturbing the roots. You may find the rootstock is way down there.

The main issue will be the timing, presumably the top is out of the ground at this time - the longer you can wait after flowering has occurred the better.

Thanks, I probably have 2-4 weeks before I need to dig them up. They’re blooming now. Do you think I could put the big soil ball into a container until I can plant them again?

You could. As above try to get as much undisturbed soil around them as possible. You could put them in large pots or maybe easier is to find an area where you could heal them in a for a while. YOu could even just partially plant the soil balls in the ground and surround the soil with a lot of fine mulch. Make sure they don't dry out and don't move them to drastically different conditions........a spot protected from the wind and afternoon sun would be best. How long until you think you will be able to replant them in a permanent location?

I have thousands of these in my yard. Above info all good. I have transplanted to may peoples yards. I just get a spade and a good bunch of undisturbed soil and move it where ever. they are very tough so dont fret to much.

Thanks for all the great advice. I'm going to move them with nice big soil balls. Hopefully they won't even know they've moved!

You may know this, but trilliums often look peaked and then go dormant and disappear in mid summer. Not to worry, it will be back next spring.