That is a wonderful scheme @adfbf87b and cemeteries are perfect spaces for it. I read about similar programs in the UK.
Unfortunately, I hardly can imagine any space with a higher fence of red tape than a cementery. Building regulations in Germany are terrible, but cemeteries beat all. That's probably why similar initiative go for street verges and neglected public land.
I need to look into this.
I like, that your approach ticks so many boxes and works on different levels. It's to learn from! 

 @326ce0aa for this project, it’s best to be clear from the outset so people know that the native plantings are in specific areas and not over internments. (This is where the reflexive knee-jerk reaction is.) Trees can be planted where there needs to be shade but native flowers/vines/smaller shrubs would be along borders, entrances, office gardens. A lot of cemeteries have contained areas where native plants can be planted but they’re unique to each location.