For long stemmed roses all summer long; when dead heading or cutting for the vase, use sharp clean secateurs and cut back to a strong, outward facing bud where the cane is pencil thick.
Make a straight cut, just 5mm above the 5 leaved bud.
This maintains the beautiful open vase shape. While you’re at it, be diligent in trimming off internally growing shoots and let those new outward facing canes grow, this is how roses renew themselves.
A couple of handfulls of manure ruffled under the mulch and your rose will respond with strong stemmed blooms.