My first guess would be thrips of some sort. Look closely at the petals to see if you see some very small insects moving around...

Thrips seem to be especially attracted to light-colored roses.

Good luck,

Virginia

How old are those flowers? Has there been rain? What have the temperatures been like? The foliage looks healthy. Thrips damage is usually along the edges of the petals.

Lack of water will affect flowers first. Petals are extremely fragile. They will fry, dry out and crisp in intense sun/heat much more quickly than foliage may. The leaves are supposed to last for months on the plant. Petals are designed to last a few days, at most. Not all roses "clean" themselves. Old, dried petals can remain on many until they are physically knocked off or otherwise removed by someone/some thing. My guess would be you simply have old, spent flowers which have refused to fall off. As long as the foliage continues looking as expected, you probably only need to dead head it (remove the spent flowers) and continue doing what you're doing until the next flowers appear.

Prune the dead flowers.

First year Rose sleep, second year they creep, and third year they leap.

Your leaves do look healthy, by the height it looks like own root? It looks like a mini rose but pictures are sometimes deceiving.

Prune to the next five leaflet and wait 6-8 weeks for its next flush (or 3-4 weeks if it is a mini)!

Good luck!

I'd think that it is working on growing roots ,and therefore can't afford to spend much energy on producing good blooms. The leaves look fine; I'd say give it time. I bet next year it will be consistently pleasing.