Newly planted perennials can take up to three years to flower
. There is a saying for perennials: The first year they sleep (establish roots), the second year they creep (spread and put on upright growth) and the third year they leap (do all of the above and bloom). If your plant was in a large container it may flower
the second year. That's one of the hardest things when planting perennials - waiting for the blooms. This plant does perform best in full sun but you'll still get blooms if its in partial shade.