I prefer non-selfdestructing berry plants, actually. Just have them regenerate a random number of berries every day or so, and that'll be fine. It's not as though anyone will actually get into berry farming in a fangame, considering how long they take to grow (let alone water).
It's basically the region map but it shows where wild Pokémon can be encountered. If a map where you can encounter an Ekans has the metadata saying it belongs to a particular square on the region map, then that square will show as Ekans' nest when you look in the Pokédex. There's nothing really to do with it.