Planted in full sun, especially in the spring.
Weigela Does Not Bloom
Certified GKH Gardening Expert
This could be due to high Nitrogen in the soil. This will cause lots of green leaves and no flowering.
You can add phosphorous to promote flowers. Bone Meal is a good way to do this.
Also proper pruning. Weigelas bloom on old wood.
Here are some links to help you.