I made this vase to display some LEGO botanicals. It's designed with a keyhole to hang from a #8 screw. The photos are of the wide version, which is large enough for two sets. The regular version is also included, which is more appropriate for a single set.

It should also work for real flowers with water, but you'll want to test to ensure that your print is watertight first--the walls are 1.6mm, which should be enough.

I printed mine upside down, and depending on your printer you may need to use supports (I did for the wide version). Printing upside down also doesn't have a lot of contact area with the build plate, so a brim wouldn't be a bad idea.