Martello wrote:
I have a few 'Cupani' Sweet Pea Grandiflora that are now about 1½
ft.
tall, growing up a trellis archway. I understand that they will, in
time, grow to at least 6ft. Do I need to pinch the tips out, as I
would on the taller varieties, or should I leave them to get on
with
growing un-pinched? I wouldn't want to harm them in any way. Please
advise.

I'd say pinch out: more side-shoots=more flowers. They'll make their
height anyhow, as long as they've got fertile soil and moisture
underneath.

--
Mike.