Pansies do best in full sun. Other reasons for lack of blooms, can be too much nitrogen which sends the plants into foliage production often to the exclusion of blooms. With a diverse group of plants not blooming, I would suspect a lack of sunlight. In early December I planted pansies and used approximately 1 teaspoon of bone meal per plant. I have watered them when it was dry, but the plants have hardly grown.
Pansies are heavy feeders, and respond well to nitrogen.
December should have been a fine time for planting. Fertilize them every two to three weeks, and they should kick in and grow, and hopefully bloom. I started to pull it up, but then noticed it looked like a pansy. Pansy plants can reseed themselves. They aren't as prolific as an impatien, but it does happen.