Ageratum houstonianum or what is it???

I am trying to figure out which ageratum it is that the Texas butterflies love so much....?

I don't see the one I'm thinking of listed in plant files. Or is it? Maybe under a different name?

Here's the plant file list http://davesgarden.com/pf/b/Asteraceae/Ageratum/none/cultivar/0/

In any case, which ageratum do you recommend in your part of the country (if not the Texas one)?

Any particular one for butterflies in Ohio?