Some of the leaves of the Wbx tutsan (Hypericum androsaemum) have been rolled up by small green caterpillars.
I suspect they are one of the omnivorous micromoths, but they could be the greater purple flat-body (Agonopterix liturosa),an Oecophorid moth . I'll have to see if I can rear one to adulthood.
In the picture above you can just see the tail of the caterpillar sticking out at the stem end of the leaf. Below, looking down the tube, you can see its head.