Companion planting is the practice of planting certain plants in close proximity in the hopes that they will help each other in either pest control, pollination, or overall productivity.  This practice is widely used by organic growers.  

It's been said that vegetables surrounded by companion plants could yield up to twice as much. 

 
 
I have been gardening for black swallowtail butterflies for several years now.  It's amazing to watch the lifecycle, or metamorphosis, of butterflies in your own backyard.

Butterflies feed on the nectar from flowers.  Plant flowers full of nectar to attract them.  Some top  choices would be cosmos, butterfly bush, zinnia, joe-pye weed, pentas, lantana, purple coneflower, salvia, yarrow, firebush, blazing star, and mexican sunflowers.