Gardening question
 

I'm having a brain fart.

There's a system of planting that depends upon the activity of other, naturally occurring plants. I used to have the list, but I don't have it anymore. Oddly enough, this is being used for a Physics assignment. :p

Anyway, the list went something like
* Plant a when the b sprouts
* Plant c when the d is in bloom

Anyone know what this is called?