Dog Fennel (Eupatorium Capillifolium)

Dog Fennel is a member of the Aster family and a perrenial. The plant has a woody stem and a very pungent smell. Caterpillars and moths are very attracted to the plant and eats it's leaves.

Dog fennel can be used for pest control when it's mixed with your garden except for moths and caterpillars. It's really beautiful when you mix it with a bouquet. If there isnt any ferns around.

Dog fennel is a toxic weed, it can't be eaten. Just because it's fennel doesn't mean that it is the type that you are supposed to veg out on. This fennel can attack the liver of livestock if they eat it as forage and other animals including people. 

Sources:

 http://www.ehow.com/about_5499392_uses-dog-fennel.html

http://en.wikipedia.org/wiki/Eupatorium_capillifolium