I’ve been reading through the last year of posts and have looked at the “hot new releases” for the past few years. Am I wrong in assuming that roses with fewer (8-15) petals are becoming more popular than roses with larger numbers, say 25 - 40. I’ve looked at some of the roses that the members here have worked with and they appear less petaled (if that’s a word). Not that I’m changing my personal goals, but it looks like this is a trend. If this is true can someone explain why? Just curious.
Yes, probably due to a greater variance of genetics closer to spe cies and shrubs being more widely available – and, also, due to the massive financial popularity of the landscape industry.
I agree there is a trend toward introductions with fewer petals.
I’ve always been attracted to roses with fewer petal count. I use more singles in breeding than most. They are generally easier to work with. Singles are seriously under rated. Stamens can be attractive in their own right.
Fewer petals often equates to an ability to produce greater quantity of blossoms.
There is no reason why roses for the landscape need have high petal count.
This said I will strive for greater petal count in the future. It’s one of those things that’s secondary for me, at least for now.
I’d rather get closer to what I’m striving for before I concentrate on increased petalage.
I agree with Robert that fewer petals generally means more blooming power. That said, I think that through selective breeding it is possible to do both - lots of blooms and lots of petals. Roses vary significantly in their floriferousness. No matter what the rose looks like, greater floriferousness (in my opinion) is always better. One of my first seedlings that I fell in love with, had a gorgeous bloom on it. Now and then, it would produce a bloom or two, but mostly I would just be waiting for the next pretty bloom. I have since learned that there are many desirable traits besides the bloom (or even besides floriferousness). A rose is so much more than the form of the bloom. Even so, I still love the exhibition formed roses too!
Jim Sproul
It might be that fewer petals (generally) equals more blooms, but it could also be the old effect that after a while, Everything Old Is New Again…
Lower petal count has an additional benefit: roses can stand rain without balling. Boule de Neige and Gloire de Dijon had to leave my garden. I was so frustrated by them, most of their flowers turned into an ugly mess.
Ulrike
The other side of the coin. In general does lower petal count correspond to a shorter flower lifetime on the bush? i.e. in general, do singles drop their petals quicker than doubles?
That’s a great question Henry. I don’t have the answer, but I remember someone pointed out to me a difference between ‘Home Run’ and ‘Knock Out’, two roses that are generally singles (KO has a couple/few extra petals). HR’s petals last about 4 days before they fall and KO a week or more. It seemed true when I paid attention. HR often doesn’t look as floriferous at least here in MN and that may be because the petals are falling faster. HR seems to share quick petal drop with Baby Love, its grandparent.
That’s a great question in general. It would be nice to compare bloom duration with genetically very similar roses that differ based on petal number.
I ultimately selected ‘Incantation’ for release because of its ability to flower so heavily that the masses of blooms nearly obscure the foliage. I don’t think its any coincidence that it blooms as heavily as it does AND that the blooms are barely more than single. (They average 12 petals per bloom)
I think it is a very real advantage for a rose to provide greater impact as a focal point in the garden, both close up and from a distance. While it was in a test bed among dozens of other seedlings, people would invariably spot ‘Incantation’ first and make a bee line for it, asking “What is THAT?!” I consider that a successful shrub.
Paul
Petal count must take up more sugars, no?
I would think so, yes.
I suspect that singleness often indicates a nearer to species breeding, though by no means exactly. A few singles hold on pretty well and lots of old very double roses drop their petals in 2-3 days. The two longest-lasting roses I know of growing around here are goldmoss and St. Patrick. Both will turn from yellow to green and keep the petals a couple weeks in 90 degree days. The petal longevity is transmissible to seedlings from goldmoss, even if they are single. I’ve had a few.
Jadea said: regarding using
“probably due to a greater variance of genetics closer to species and shrubs being more widely available”
I assumed that due to mutations and crosses of the various cultivars that the gene pool of new roses would have a greater, if not different, gene pool. If I’m reading correctly, she is saying that rose genetics has narrowed. My brain is starting to hurt again.
I like what Fara said, Old is new again.
No, lol. I (he, btw, midleading name, sorry) was just implying that a heavier species influece has lowered the petal count on average. This is as opposed to the huge influx of F1 and F2 Peace hybrids that we inherited from the 50s, 60s and 70s.
Got it, thanks. That makes sense. I was digging through the two books from the RHA and previous posts trying to figure it out and it was NOT coming together. I was getting ready to start looking for the old college botany books.
Sorry about the gender screw up.
I suggest viewing a listing that gives Peace as a parent/grandparent with a “skeptical eye” as there have been some comments over the years that sometimes commercial hybridizers gave genealogies that they thought would help sell the introductions.
That is an interesting point about species roses tending to influence more singles. Many are singles. For the inheritiance of double blooms there are two strong components.
-there is a major gene that needs a dominant allele for there to be blooms that routinely have more than 5 petals. Roses only have 5 true petals and the rest are referred to as petaloids- converted stamens and in some cases even pistils.
-there is a quantative aspect that in the presence of this dominant allele then multiple genes with their various alleles can contribute to the degree of doubleness.
In a cross of a single flowered female Rosa setigera x a semidouble diploid modern rose I had some single offspring and some double offspring. (it fit the 1:1 ratio expected for this semi double rose if it was heterozygous for this major gene). Out of the double one most of the offspring had very double blooms, much fuller than the semidouble parent- often over 100 petals!!! So this wild rose had many alleles at these minor genes contributing to very double blooms in the presence of this dominant major allele. They were masked in this female.
We see the minor genes influence with semidouble roses because they have the dominant major allele allowing their expression. Because of the additive nature semidoubles have a difficult time producing very full roses unless we happen to cross them with very double roses or a single with a lot of hidden power in regard to these minor genes.
I find inheritance of doubleness fascinating and to some degree tried to take this understanding into account in my crosses trying to generate roses that are a good balance for doubleness. There are so many traits to select for and I like singles and semidoubles too that it tends to be a minor factor when I am considering parent combinations.
What do others do in this regard in terms of planning crosses to aim towards a particular petal count?
Sincerely,
David
Petal count is rarely a big consideration in my work. I value traits like vigor, health and overall performance much higher than the form or petal count (or even color!) of the individual bloom. However, that doesn’t mean than I don’t select for doubleness and aesthetic qualities of bloom. 
Paul
Right now I’m working on foliage, disease resistance, saturated colors, repeat, fragrance. Somehow petal count figures way down on the list of those things I’m striving for.
I’m guessing that I’m working at integrating more species into the mix than most. Integrating species is slow work.
Yes, I get a lot of singles right now but seedlings with more petals do come out of these crosses. All things being equal I will no doubt try to work toward higher petal counts as time goes by.
Actually it’s sort of like delayed gratification. I don’t mind waiting if I can create something different.
Regarding petal count and tendency to hang onto petals, I agree with Larry that there are good examples on both ends of the spectrum for early and late petal drop. One of my favorite more clean and floriferous seedlings, is from a cross of (‘Marmalade Skies’ X ‘Baby Love’) X [(‘Marmalade Skies’ X ‘Baby Love’) X (‘Marmalade Skies’ X ‘Baby Love’)]. Unfortunately, it hangs on to its petals forever! One of the major rose growers commented that the bloom clusters reminded him of hydrangeas, but the problem with petal drop (lack of) “killed” it. This seedling also strongly passes that trait on to its offspring.
For shrub types, I don’t plan crosses so much for petal count as for the other important traits in a shrub - cleanliness and flower power. However, for the HT exhibition types, I always try to have at least one of the parents full on petals.
Jim Sproul