In article , K
writes

Theory is that a) it stops energy going into fruit production b) it
encourages a second flush (especially if you remove a few inches of
stem back to a decent bud point) c) some roses don't drop their petals
very well and dead flowers look tatty.

It depends what sort of roses you grow. If you're growing species roses
which don't have a repeat flowering, for example, deadheading is a
waste of time from that point of view and deprives of a crop of
beautiful hips.

I think that the two lovely climbing roses in my garden don't have a
second flowering. But, weheter for them or other roses, I've always
wondered exactly where to dead head. Just the head and a centimetre or
two of stalk, or further back (eg, beyond the split in the stalk where
multiple heads come off)?

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regards andyw