Considering this, do zinnias grow back after cutting?
Zinnia flowers produce large amounts of seed. Cut back the faded flowers early in the season to direct the plant's energy toward producing more flowers rather than setting seed. You don't have to wait until they've faded to cut the blooms.
Also to know, should you cut zinnias?
It's time to cut! Cut deeply on the plant to get a long, strong stem. Remove the foliage and don't be afraid to cut off side shoots on the main stem you just harvested. Zinnias are a “cut and come again” flower, so when you cut the plant “hard,” it responds by sending out even more long, strong stems all season long.
Zinnias are annuals, so they'll grow for one season and produce seeds, but the original plant will not come back in subsequent years. Double-flowered zinnias have numerous rows of petals and their centers are not visible.