The flowers are mainly useful because they indicate that the new potatoes are big enough to eat. No reason to take them off.
Sometimes old codgers pull young'uns legs!
If you only cut one root, I am sure it will survive.
Remove them. Branches with green leaves are stronger growing than red and will take over the tree if left.
You mention Rose of Sharon in your title. Isn't that Hypericum?
I think you will have to wait and see. Sorry.
Beans, beans and more beans. It is impossible to buy beans as good as those you can grow.
Asparagus is not very nice after it has been frozen IMO.
Don't want to rain on your parade, but swedes are best grown by a farmer in a field and purchased from a shop. They are cheap and plentiful and as large or small as you want them.
It is a very nice idea to give each guest a packet of seeds at the wedding. Maybe beside their place if it is a sit-down meal.
Just enough. Plant in a block. 45cm apart each way.