It depends why you are growing it. If grown for decoration leave the flowers on if for culinary use then keep the flowers cut off and the foliage young as this improves the flavour.
because you cut them off from the roots
It is believed that adding sugar to the water for cut flowers provides the flowers with a food source since the flowers have been literally "cut off" from their food supply.
Yes.
Chrysanthemums flowers will die and should be cut off to encourage more flowers to bloom.
He cut the flowers off her bushes.
Yes, if you 'dead-head' or cut off the heads of sunflowers, the plant will usually continue to produce more flowers. This varies somewhat with the variety of sunflower and the bushy type will produce the most flowers when flower heads are removed.
Cut off the old flowers the foliage will die back naturally in the Autumn.
I have a plannt like that. It has purple flowers though. I havnt really found out for sure what it is. But from what I was told its probably purple sage. I think the sage bushes give off an odor like that.. just giving you a place to start
Jem cuts her flowers because he was ager at her. and because he was tried of her talking about him, scout and Jem and also their father.
Wait until the flower spike dies back then cut it just above the leaf.
Cut off the spent flower stems and leave the leaves.
Yes, it will help extend the flowering season of the plants.