How to keep mums to stay fresh

Did you re-pot them

Cut stems underwater and then crush to open fibres inside stem - add sugar to water if you don't have cut flower cristals.

I am assuming that they are in their original pots, sitting o a porch or something. . Many times they are potted in less than optimal soil. You either have to water daily, or add a better soil mixture. If you bring them in, and yo have heat on, you really have to water regularly.

My experience with potted outdoor mums is to never let them dry out. Unlike other flowering plants that will revive if you skip a day, mums often wilt, discolour and stop blooming .

They obviously need to be watered.