I live in a poor, blighted neighborhood. I grow in every part of my yard, on my porch, up my porch,in toilet tanks along my driveway,you name it.
I love edible plants that can care for them selves,sunchokes,blackberries,mints,creeping charlie,Rose of Sharon, mimosas, box elder,plantain etc,are all welcome in my crazy yard, but some edible "invasive" scare even me.
Not kudzu,but running bamboo, willows, some figs, etc.
Still I would love a handy source of bamboo or willow that proliferates like crazy and I would love to put these bad boys of vegetation in one place and see what happened.
Did I mention the blight?
So, yeah, I even have a lot in mind, sitting , taxes unpaid(yes I might buy it, but no I can't afford it). I have dug around in it, its full of debris and probably full of lead and worse.
If this land were mine, no, I would not unleash these beasts upon it, but only because The Man would be up my ass in heartbeat( I have been cited for my own yard).
The current owner of the lot in question have had the place "fixed" for them by the city, and the cost added to the delinquent tax bill.
Would planting here be unethical? I struggle to pay enough attention to my own "crops" after each spring planting, so I only truly self sufficient kind of plants would be worth doing.
Plenty more vacant lots around,and if this one takes off,it could be a kind of nursery...
If I were you I would go for it and not lose any sleep on the ethical issues. Sure it's not your land, but no one is using it anyway, and throwing some bamboos and willows on it is not going to ruin it. Maybe eventually after the city or bank takes possession of the land they will lower the price and you can buy. Either way it sounds like the land is locked up in limbo for the time being, may as we'll grow some plants.
When lots belong to the city in depressed areas, they actually have a negative value. I have looked at hundreds that were listed at less than $100. If you agree to keep the lot clear of garbage, you may be able to negotiate tax relief. Go down to city hall and offer them $25 for it with 25 years of tax relief.