Mine aren't doing too much either. I think we just have to wait for warmer weather.

I find they need about a half-day of sun and regular fertilizing. They bloom non-stop for me. When it's cool like this, I water every three days or so; then every day when it gets warm. And I use Miracle Gro every time I water which really pushes out the flowers. I do this with all my containers, 1/4 teaspoon of fertilizer to one gallon of water. Containers need lots of food!