Can I grow new plants from the seed heads of blue bells?
If not should I cut the seed heads off and if so when?
Hi. Yes, bluebells will seed and grow new plants (several years before flowers though) so if you want that to happen then just leave the seed heads where they are. If you don't want any more bluebells then cut the heads off and discard. It is actually easier to just get a firm hold on the seed head and pull. That way the whole stem and head will be removed. This is the way to pick bluebells too - don't bother cutting.
Yes you can but the chances are they will be hybrids with the invasive spanish ones. It'll take about 3 years for them to reach flowering stage.