I own a plant of 'Princess of Nassau' which has continually bloomed from the beginning of summer to the first heavy frost. It is placed on an east wall where it gets a goodly amount of light, and I don't think I have ever fertilized it In the 4-5 years I've had it. every book I have ever read about this rose has said that it only blooms once, but like I mentioned before it keeps putting the flowers on.
The Princess of Nassau is one of those roses that starts to bloom really late in the summer even as late as the end of July or into August. Then it will continue to bloom until it is stopped by cold weather. It would appear to only bloom once if it grew in a cold climate, because it is so late starting. In the warmth it would bloom much longer.
