Claire Petersky wrote:

Last night we had a windstorm and I woke up this morning to find the
rose trellis over on its side in the garden. The trellis is an arch,
about 7 feet in height.

I never prune the climbing roses on the trellis for two reasons: a)
they say not to prune climbing roses and b) I don't want to get on a
ladder to prune them when they're up so high. But now they are
conveniently lying on the ground, and I figure, if there's any time to
prune them, it's now.

Claire, this may be too late, but I hope not. The identify of your
roses *is* important. Bewa some roses only flower on old wood, such
as Cl. Peace and most ramblers. So I would prune such a rose very
sparingly, really just removing hips and giving it a good deadheading.

And some roses are reputed to like no more dead-heading than just
snapping off the spent flower heads. So...the names of your roses do
matter, and one-size-fits-all advice could lead to a year without
blooms. Once-blooming roses are best pruned after the spring flush, not
in the early spring.

Assuming it is a repeat blooming modern rose, don't shorten the
climbing canes (the really long basals), but *depending* of the way
your rose grows, you can "prune" your climber each year by shorteing
the laterals. How short depends on how your rose likes to grow and how
much you need to restrain it. I generally cut back to nice stout wood,
about pencil sized.

If any of the basal/climbing canes is very old and if your rose has
lots of growth, you can remove any old, unproductive canes you may
find.

Good luck. I've used 3/4-inch galvanized conduit pounded into the
ground to secure garden structures. You pound them in and then strap
them to your trellis with U-shaped brackets. You can cut the conduit to
size using a hack saw.