Many roses take 2-3 years to settle in and really start doing their own thing. I do not know the rose you mention, but it may just be busy growing a good root system and will burst into bloom next spring.

But most roses like water--not flooding, but a good ready supply of water at regular intervals. Perhaps try watering it more often and see if that improves it. I have a couple roses that start bursting into bloom after a couple really good waterings.

Kate

There are a few different Summer Snow roses, the floribunda, climber and a miniature. If it's the climbing version it may take a couple of years to establish and bloom. If it's one of the other two it should have given you some bloom by now. Since it's already pretty late in the season I'd wait for spring and if it doesn't bloom then I'd replace it. It is possible to just get a dud plant. It happens.