When should I nip back new growth on chrysanthemums for more blooms?

Promote bushiness by pinching each shoot beginning when it is 6 inches tall. Repeat this pinching each time shoots grow an additional 6 inches. Stop all this pinching no later that 90 days before the normal bloom date. July is when most of these plants start to develop flower buds, and you don’t want to remove those buds.

I've always heard pinch them back til 4th of July. Since this is the holiday it is easy to remember.

I have always followed the rule, pinch back until the 4th of July and have had good success.

I just deadhead regularly and have had beautiful blooms all spring, summer and early fall.