Who's Your Daddy?

[Pardon the title; we just couldn't resist ...]

A request was made that we discuss a peculiar phenomenon noted by a fellow rose gardener. His query:

Why are the second generation of blooms sometimes 1/3 of the size of the first blooms of the season?

The short and very general answer is that a rosebush is not a widget factory. Blooms will vary not only in size, but also strength of scent and, depending on the rose variety, color.

As an example, below are photos of two roses from the same shrub, a hybrid tea called Sterling Silver. The plant is about 6 ft. tall. The larger bloom came from the top of the plant; the smaller, from the midsection.




The smaller flower has suffered quite a bit of insect damage which, in addition to its more shaded position on the plant, may have contributed to its reduced size.

What is stranger still, none of the flowers currently open on this particular shrub have the signature citrusy scent which, apart from the lavender/pale mauve color, is the selling point for this variety. Perhaps the scent evaporated in the recent heat wave?

Getting back to the original query, it is our belief that environmental factors are the cause of a consistent difference in bloom size. The rose bush in question had a nice rest over the winter, enjoyed some spring rain followed by balmy temperatures, and then put out its best blooms first. As the weather became hotter and drier, the plant suffered some stress, so the later blooms were smaller.

This is our conjecture; any “rose whisperers” in the blogsphere are welcome to ring in with their thoughts on the issue.