Is your feature request related to a problem? Please describe.
Because my Bedwars plugin doesn't protect plants to be stolen from flower pots, I needed a worldguard flag to fix this issue.
I noticed that the only way to prevent players from 'stealing' plants from the flower pots, is to set 'build to deny'.

Describe the solution you'd like
I would like that in a future update, you can add a specific flag to prevent flower pot interactions.
(Just like the 'entity-item-frame-destroy' flag works)

Describe alternatives you've considered
As you understand, it is not possible to deny players to build in a Bedwars game.

I'm looking forwared to your response.
Thanks in advance.

WG is primarily a protection plugin and flower parts are part of the standard building protection. You don't need to set any flags for it to protect flower pots.
If you have hyper-specific needs for your bedwars game, you should take that up with your bedwars plugin. WG will not bend backwards to deal with these hyper-specific needs.