Identification of a possible mint?

Question

I have been trying to attempt to identify the plant on the left to no avail. I have identified the plant on the right as Selfheal.

http://img158.imageshack.us/img158/5513/needidxt1.jpg

This was found in South Eastern Ohio. It was found in a relatively open area. The soil is dry and mostly made of clay. The spot that it preferred was also rocky and has been undisturbed by a lawnmower for well over a year. It's in the same area as Wild Bergamot so the soil may have a high lime content.

The stem and leaves are hairy. The stem is round and also tough and rigid. The leaves grow opposite of each other.

The flowers grow in round clusters situated around the leaves.

The plant possibly grows from rhizomes although I did not get a large enough root/rhizome sample to determine it.

The flower has the typical mint flower look. It has one petal on the top and three petals opposite on the bottom.

Answer 1

Not a mint because of the round stem - mints have square stems.  Possibly a knotweed.  What is scale of the plant?  

Answer 2

mints have squared stems.... is there scent to the leaves?....  

Answer 3

google it.