Yes, I know you can override the plugin objects attributes this way — and I am currently doing it this way. But, like I mentioned at first, and like @kwik mentioned, this is only a band-aid solution. Anytime information is changed for the landscape area, it reverts back to the original attributes. And when you have 12+ different species it seems like a lot of tedious work I'm trying to avoid.
Is there a way to create your own landscape area? I've only found tutorials to creating custom plant symbols.