This is a modern shrub rose, and like many of the modern roses, it's unfortunately lacking in fragrance. Still, it's a lovely rose to look at, and adds a nice splash of color to the garden. You will get a repeat flowering later in the season, with any luck.
Just make sure you deahead it, and remove old blooms to help encourage it to repeat. The knockout was originally marketed as "self cleaning", which is to say no deahdeading required. However, experience has shown that you definitely improve the flowering qualities by picking off spent blooms. Easy care, this has a reasonably compact growth habit, and looks at its best in a mass planting.