Plant turf wars
 

I'm planting a mixed flower border at my new place, with shrubs and flowers and the ornamental sweet potato Ipmoea Margarite. I just found out that the Ipmoea and the sunflowers I was planning to use are allelopaths, they secrete substances protecting their area from certain other plants that will prevent growth of those other plants.
I had no idea that plants were involved in turf wars like that. Interesting.