fruit tree planting requirements

Basically the screenshot. I've seen a reddit post that claimed 20 fruit trees were possible inside the greenhouse. Reading the wiki page, it seems like our lord and savior CApe had a few moments with balancing the trees, and as I've found around, ultimately the last amount that we can have is...

Hi Stardew community, is there a way to visibly see the spacing requirements for planting fruit trees and the different placement options? Stardew Valley game ---> "Only grows if the 8 surrounding "tiles" are empty." is not making sense to me. This is how I understand it: xxx x0x xxx However...