First congrats on getting even one agapanthus to bloom in your climate. This heat loving bulb does not like the cold winters or high rainfall of Western Washington. Second it appears your bulbs are small and may still be bulking up to bloom. The clumps that flower well in warmer climates are quite large. I suggest you add Osmocote Plus around the base of each plant now. During the warm weather or August your bulbs can grow stronger and perhaps you will see more blue blooms next summer. Leave the foliage to wither and die until spring. Good drainage, full sun and warm weather are key. The color is amazing on this variety and worth waiting for.  Keep growing, Marianne Binetti