Another picture. Thanks!

One last picture.

Sawfly larva (also called rose slugs) are dining on the undersides of the leaves. Look on the back of the leaves very carefully and you will see little tiny green caterpillar looking things. You can pick them off by hand or use an insecticidal soap like spinosad.

Yep rose slugs are munching...
Pick them off. Can be found on the underside of leaves or on the top side depending on what kind you have.
OR
Spray with safers insecticide soap after the sun goes down so leaves do not get burnt.
Same with a spinosad product.
Follow directions carefully...

Any idea what's causing the brown spots?

Rose Slugs are causing some of those spotty brown/whiteish areas.
Keep the bush well watered in your heat and do not over fertilize as that also causes leaves to brown and curl.

So in the Spring when you first start seeing holes and
those spotty areas start picking those Rose Slugs off or spray safers insecticide soap/ Or spinosad before it gets worse.
You will have to repeat later on...

I grow only own root roses so I'll let someone else answer the suckering cane question...

This post was edited by jim1961 on Wed, May 29, 13 at 19:26

I am not sure what the OP means by "sucker canes." A pernicious sucker on a rose is a shoot that comes from rootstock, below the graft. Unlike good shoots from the base, these will grow for months without setting a flower bud. If you have rootstock suckers, you must dig down to the point of attachment and rip the shoot out of its socket. Otherwise it will grow back.

However, it's unlikely that you would have three rootstock suckers on one plant. So maybe these are good basal shoots that will bloom soon.