The bluest rose I know of is Kordes Blue Bayou, which is not sold in the US, or possibly anywhere, anymore. I purchased it from Hortico years ago, grew it for a number of years. It lacked vigor and dwindled away, ceasing to return after one winter in 2017 or so.

Lots of times Love Song seems just as blue as Blue Bayou was.

The funny thing, as I just found out, is how many growers of this rose like it and rate it excellent on HMF. I couldn't believe it, and their blooms were about the same as mine. Diane

Love Song looks a LOT better to me than does Blue Bayou.

And, no, Moses ,I don't believe there is and probably never will be a rose of that true blue colour. I seem to remember reading that it'd be genetically impossible,but don't have any proof of this.

Nope, no true blue roses. First of all, roses don't naturally possess the gene for "blue-ness". But the real problem is the cellular pH of rose petals. Even if the rose had it, the chemical pigment responsible for "blue", delphinidin, is sensitive to pH. In a acid environment it presents as red. In a less acid environment it turns pink. In neutral conditions, it turns blue. Unfortunately, rose blooms are slightly acidic down at the cellular level, which would push the delphinidin into the lavender and purple range, instead of true blue. Also unfortunately, roses are not hydrangeas so changing the soil pH does nothing to change the pH of the blossoms. The "blue rose" (Applause) that was bred by Suntory ran into this problem. Even though they genetically modified/gene-spliced the rose to contain the gene for delphinidin (from a pansy, I think), because they didn't breed for a less acidic bloom, the flower is lavender, at best. 'Applause' had the right genes, but the wrong pH to present as blue.

For us ever to have a real blue rose, it will require some more genetic changes, mostly to the acidity of the rose petals. I've seen research that says there is quite a bit of natural variation of bloom acidity between rose varieties, so it seems it would be possible to breed a variety with higher pH, and then insert the gene for dephinidin, either through "natural" hybridization with Applause (which already artificially contains the blueness gene), or by again gene-splicing the gene into the higher pH rose.

Someone, someday, will do it. It just comes down to perseverance and money.

Diane, sorry Blue Bayou didn't work out for you. Had it thrived for you and probably for many others who tried it, it would be up there in the charts instead of being a relatively forgotten rose today.

The more I refer to HMFR for help the more I come away scratching my head in a state of perplexity. Roses I have had great success with are often receipients of low reporting, and vice versa.

Moses.

fig, you're a fountain of knowledge!

Moses.

Moses, thanks. Thinking back, Blue Bayou probably dwindled so much because it couldn't take our zone 7 winters. Seriously. Western Europe is pretty mild compared to lots of the US. Parts of London are zone 9. So what I mean is, BB persists in Europe because of fairly mild conditions, maybe, and gets good reviews from Europeans. I don't buy those reviews. At the same time I got BB, I got three Bernstein-Rose (Tantau) plants from Hortico. They are still thriving in my garden and currently in bloom. Now there's a rose that deserves good reviews. it's also used in rose breeding a lot from what I've noticed.

Fig, I totally agree with you on genetics, and the persistence of rose breeders with some money at hand. The Japanese were really obsessed with blue roses a while back. They may be the first to come up with a true blue rose. Meanwhile, I'm perfectly happy with my two very large Love Song roses, currently sporting lots of very large blooms. They've been about 6 inches across all season. What a rose. Maybe they'll thrash Julia Child for the Last Rose Standing prize in my garden when the hard frosts start. Diane

Moses, nah, I just know a LITTLE about a LOT. Just enough to get me in trouble most of the time. But I'm deadly at Trivial Pursuit, lol. I'm that kid that read the encyclopedia after lights out, under the covers with a flashlight :P I still read much too much...at 3am. I also spent three years taking random college courses before I ever settled on a major. Wasted money? Maybe, but it was fun. But sometimes knowing where to start in a search for more info is often all it takes to look a lot smarter than you are, hehe.

I will admit to speaking three other languages, and a smidgen of two more, which lets me read articles in their original language. WARNING: do not trust Google Translate. It's getting better, but still prone to egregious errors. It is especially bad with French (soooo much is dependent on context and understanding idioms). Nuance can be everything.

P.S. I have a terrible time with knowing I should know something, that I read something somewhere...and then spending hours tracking it down. It's a curse. A curse, I say!