Allowing mixes grow-zones

[Hozuki]

Hey, just a quick thought I had just know seeing it ingame due to me switching the selected plant in a grow zone:

Why not allow a mixed grow zone with trees and other brush-type plants (like this: http://i.imgur.com/kRBktSg.png) between the otherwise empty slots from tree to tree

It would be super space efficient, which is something core to basebuilding.