Verbascum Gainsborough pruning ?

Hi ! Just joined the forum, looking to get some tips from peaople in the know. Just had my garden done and looking to keep on top of it now and learn a thing or too in the process.

My first question is...I have loads of new plants in now and some of them are starting to lose their flowers one example is the Verbascum Gainsborough. Am I to just leave them to wither down or should I be pruning them back.

 

Leave them to self seed if you want them to continue, or collect seed as they die after they have flowered.