Pruning strawflowers isn't usually necessary, but pinching off flowers as they fade can help encourage a few more blooms.

How do you prune a strawflower?

Strawflowers don't need to be pruned regularly. However, deadheading the plant will keep the flowers blossoming.

Do you pinch celosia?

PINCHING: Pinching is not necessary for all species of Celosia, but is still recommended to increase branching (the number of stems and flowers produced) and uniform flower size. ... When plants are 8–12 inches tall, pinch the stem with your thumb and index finger or use sterilized scissors to remove the growing point.