If it's large enough, you should divide it. In the early spring, dig it up and divide it into two or three smaller clumps to replant. It does grow readily from seed, but the resultant plants may not come true.

So far it hasn't reseeded, so I'm not sure if seed would come true. I'm a bit reluctant to divide it. I'm afraid I might kill it. :) I've divided daylilies, shasta daisies, and irises before, but agastache looks so delicate.

Is there a way to take tip cuttings? If so, when is the best time and how? I do have rooting hormone that I use with other plants.

Thanks again everyone.

The primary method of propagation of this plant is by division. I've seen several sites which mention stem cuttings, but I've never experimented with it. Agastache should be divided every once in a while, just like many other perennials. Be brave!