I purchased one of these last summer. Last fall I divided into three plants. They have been in bloom for more than a month for me. It seems odd to me that you don't have blooms. Maybe your plants are still too small.

Mine are just now showing buds. Location, both your zone and how much sun and when will determine when they bloom. I usually pinch about half of mine back in mid spring to delay blooming so I can get two bloom periods. They are easy to divide to make more plants. I started with three plants four years ago and now have four batches with more than twenty plants each, and have been giving them away for the past two years (I don't have anymore room).