I’m comment here because Anne Gibson has tried and failed so I’m checking. But also Narayana got some cuttings and has successfully grown and shared some of these. So if anyone wants any cuttings please comment.
I too have had great sleep benefits from taking Passion flower (Passiflora incarnata) supplements. It can be purchased currently as a plant (50mm tube stock) from All Rare Herbs for those interested. Mudbrick Herb Cottage also has some stock available Nov-March.