Do not throw away your first Piilu. You can try to gently remove some soil above it and see whether it is sprouting. Or just wait. You planted it deep enough to protect the crown. For the same reason, it might take some time for the shoots to reach the surface of the ground. I replanted my Piilu a couple of weeks ago. It did not have any top growth at that time, but it had multiple sprouts starting from the crown. They still did not emerge.

If you have bad drainage, the roots and the crown of your Clematis could rot though. I would dig it up and examine. You can have the same problem if you plant another Clematis at the same spot.

As for your new Piilu, there is no need to cut it back to the ground. Pruning to the first leaf node (about 1-2 cm above the first pair of leaves) is recommended. This will help your plant to get established and will encourage branching. You can also pinch all new shoots to get even bushier plant. Piilu blooms on new wood, so it will still bloom for you this year, although the blooming might be delayed.

I've been trying a modification of something I saw on a rose forum this year. The original post was about "sweating the rose" that hadn't shown basal breaks (new canes from the ground or on what canes were left after cutting out the dead wood, I think). It must have been a small rose that the poster said a nurseryman "sweated" by placing a white 5 gallon plastic bucket upside down over it. The purpose was to warm up the soil to encourage the rose to grow.

Now I had more "non-emergent" clems & rose bands than buckets, so I put the largest black plastic nursery pots I had over the little nubs that remained of last years growth. When most of my clems are up & growing, I do get a little anxious about the ones that aren't, and tend to poke around the surface soil to try to loosen it up a bit and search for underground shoots.

Before I read te post I had noticed that under the surface the soil was still a bit cool, although we have been having some unseasonably warm weather followed by the usual cooler Spring temps.

I resolved to not check them every day, and after the third warm day after the covering, I did see some little green nubs poking up. These stayed uncovered as I didn't want to fry them. I do check the still covered ones every day now.

One downside to this method is that I found a slug in one of the pots (as well as everywhere else). I guess they like the extra heat as well.

I don't think I would want to try it in a warmer climate though.

Marie in ME

I've found Piilu to be a really good bloomer. You should have blooms this year even though it is newly planted. I agree not to prune to the ground, that much isn't necessary. The old one may not be dead either.