Why does my ‘New Dawn’ climbing rose bloom only once in the spring, when it is advertised as blooming all season? -Jane

If your ‘New Dawn’ is blooming only once, there is a good chance it has reverted back to its parent variety, the single-blooming ‘Dr W Van Fleet’ rose. This may have happened before you even bought it, or it may have happened as the plant grew.

‘New Dawn’ developed as a “sport” of ‘W Van Fleet’ rose. A “sport” is a new variety, or new growth habit, that happens by chance (a genetic mutation) and is then propagated, as opposed to a variety that is developed through breeding or hybridization. Unfortunately, some varieties are more stable than others, and it’s not uncommon for occasional branches, or even a whole plant, to revert back to its parent form. While you can’t completely prevent this from happening, you will have better luck if you make sure to use the feeding and pruning practices specific to that variety.

Another possibility is that some rose gardeners claim that certain varieties, including ‘New Dawn,’ go nearly dormant during very hot summers, which could be contributing to your problem.