Blanket flower (Gaillardia), foxglove (Digitalis), snapdragon, blackeye Susan vine... just about everything that flowers looks and grows better without spent blooms.
It may seem like you're eliminating color but in every over the hill flower there is brown. Removing the brown immediately clarifies the flower color and you'll be spurring the development of new buds, too.
Foxgloves (Digitalis), hollyhocks and delphiniums often acquire this ridiculous appearance because the gardener thinks "If I cut it, then that's it." Not so. f you deadhead before ripening seed takes control of the plant's growth, more flower stems will develop from lower on the main stem, or from the crown. So, when the inches of seed forming below the flower exceed the inches of buds coming above, it's high time to deadhead these spikes.
Don't pull off petals and leave the seed pod.
As with cutting back annuals in containers, you will be more confident with your snips once you make a positive I.D. -- what's a bud, what's a seed pod.
Blackeye Susan vine (Thunbergia alata) is one of those plants with just-forming seed pods similar in appearance to half-grown flower buds.
A stem that was deadheaded two weeks beforehand, now full of flower buds. Above, insert photo: An update; same vine 3 weeks later.
A snapdragon flower stalk bearing only seed pods above.
Feel and peel, in this case -- the pods feel drier than the buds, and gape open at the tip when you press them. Peel one open and you can't miss the difference between petals ready to unfurl (center), and petalless seed pod.
More about deadheading!
Blanket flower Gaillardia