I think it depends on the daisy you have! I am not an expert on those plants & I usually only dead-head my daisies from where the petal meets the stem, once they stop blooming.
I have perennials that have turned brown from the top of the stem down & those we cut back to just slightly above the ground.....for winter. They return in the spring.
I am sorry I couldn't be more help, my dear.
__________________ Love the earth...Love the creator.(Rom. 20:1)