I have three potted Ajuga plants in my back yard that have long stems with leaves growing off of them. This usually means that they are ready to be propagated.
I cut the start, which it has a “V” shape to it, and set the bottom of the “V” in water for a week or two. I bought some seedling trays that work well for this. You can also use a 9×13 glass pan (not metal). I find these pans at the thrift store.
Then, roots start to form. Keep this in a shaded spot to protect the young start.
Once the roots have formed, I plant the start in soil and water it well. Tomorrow morning I will water it again to make sure it stays moist as it establishes itself in that soil.