Bushes not planting?

[ethre]

Can anyone explain to me why my bushes die ? They aren't next to rocks or anything. It seems like they will only plant in certain spots. Do they die when I walk through them?

 

[Ras]

No, but there are dead spots where nothing will grow. They should be pretty rare and limited, though. The only other thing is you can't have more than like 12 touching, including trees.