Question:
Am I allowed to cut flower or branches from public areas like parks? Or even overgrown areas around my house that either belong to the public or the government?
Answer:
If they are overgrown or for some other reason no one cares you can cut in a way that doesn’t damage anything- But it is a middas chassidus not to:
Have a good Yom Tov
Sources:
Shulchan Aruch CH:M 359- 1.