Q.My Rose Bush Produces Huge Blooms, Which Last For No More Than A Week, But Do Return Later In The Year. Why This Short Initial Sho
rt flowering period? Just to add, more by repetition, my first flush of roses (about now) produces extremely large and beautifully scented blooms. However, they begin to wither within days. Later in the year, they will come again, albeit with smaller blooms which seem to last longer. The plant is healthy, well fed and watered, and so many passers-by stop and comment on the size of the flowers at this time of year. I simply don’t understand why they flower for such a short time.

Certified GKH Gardening Expert
Normally the size of the bloom is determined by the pruning method. Do you cut the rose bush back severely in the spring? If so, you will get larger blooms but less of them in the spring.
Here is more:
https://hgic.clemson.edu/factsheet/pruning-roses/