If you are not growing Catmint Nepeta - "Walker's Low" in your garden, you really need to stop and ask yourself, why not??
It was named Perennial of the year in 2007, and with good reason.
I am seriously telling you, you must go out and get this plant. Do not be like my daughters and wait 5 years after me telling you something, and then you come to me and say "oh, you know Mom, you were right, I should have listened to you." Don't be like that, especially the part about calling me Mom, because that would just be weird.
***Edited to add*** This is not catnip! It is a completely different plant. It doesn't attract cats at all. It's a wonderful perennial flowering plant.