[Clarabel]

makes the garden look horrid with "dying" plants all over. Or do they need to die off themselvse?

At the moment its the poppies and chives.

[Sive]

Chop your chives right down and they will regenerate very quickly with very appetising new growth.
As for perennials generally, you should keep dead-heading to encourage flowering. Otherwise, as I am not an expert, I have slowly learnt which ones benefit from an early chop. For instance, the hardy geraniums can give you a second flush of fresh foliage and flowers if cut right back after flowering.....also astrantias. You'll learn by experience.
As for the later perennials, it depends on whether you're a neatness freak, or whether the skeletal shapes appeal to you over the winter...and the birds and insects probably benefit from a relatively "untidy" approach.

[James Kilkelly]

This article may be of interest to you Clarabel...... How to prune your perennials when they look a bit tired.