Empty out the pot and look for the white root with tip about to sprout up again. If not sure put repotted root and soil in a protected spot for the rest of summer and check again in September. I just came across this last week when emptying out pots with no green growth! One had what looked like a viable root!

I have had this plant for about 4 years now and most years it came up
later. This year it has not sprouted at all. I am leaving it in the ground in hopes
that it might sprout through really late.

Thanks so much for the advice. I guess I'm not the only Calgary gardener experiencing the results of that horrible June weather we had. The plant is in the ground so I think I'll leave it undisturbed for now and give it another chance. Here's hoping all those other "dead" things will eventually sprout as well!

The roots store food for the plant over winter. In spring the plant starts to grow by using up this food reserve. It will not make more food until the new leaves are almost fully developed. If the new growth is frozzen off, the plant needs to start again, but this time it has less stored food.

You can guess what happens. At some point it runs out of food and is dead.

I would not disturb the plant. This will only remove more roots and make the situation worse.

Leave it alone - but my guess is that it is gone.