Williams' Double Yellow ploidy

With Hazeldean and several other hardy R. spinosissima altaica hybrids turning out to be triploids, I am wondering if Williams Double Yellow is a confirmed tetraploid.

Anyone know? I would say tetraploid but it has no listed offspring.

I suppose I could assume its tetraplod because it isnt a altaica hybrid. Seems like there has been some speculation that R. spinosissima altaica isnt really a spinosissima or something like that.

I do remember someone from Sweden saying that it was more hardy than Hazeldean though that may not be the case in Canada.

I plan to use it a lot more next year. It produces lots of pollen. It has not set any open pollinated hips for me.

This rose has been interesting to me and I have wondered why there is so much interest in Hazeldean yet it almost seems like there is little interest in it. It was first brought to my attention quite a while back when Mr. Radler made a comment about it being reasonably disease resistant and that it might be usefull to include in ones hybridizing.

Its a nice rose for me. Good yellow color. Grows a little slower than some of my other spinosissima spinosissima altaica hybrids.


Hi Steve,

I have a little sucker of WDY in a pot. After it rebounds and has some nice root tips (hopefully it will), I’ll confirm it. What a beautiful rose. It sure suckers a lot! It seems like on the plant I have access to that the pistils are deformed and that might be what is limiting female fertility. There is a couple hips forming on it. Hopefully I can get them in time before they fall and try to germinate the seeds.



I had noticed that, its the same way on Beauty of Leafland. The pistils are deformed and there are few if any stamens.

Beauty of Leafland never formed any open pollinated hips before this year. This year, its producing several. Perhaps WDY is similar, once mine is a little more established it will produce some op hips. My rose was small last year but has started growing well this year. It produces a very impressive number of flowers when its blooming.

It is most definetly a beautiful rose.

WDY pollen on Carefree Sunshine has produced a very large hip.

“I do remember someone from Sweden saying that it was more hardy than Hazeldean though that may not be the case in Canada.”

SteveJ, it was someone from northern Finland who said this in another thread, though not me. He talked about a very old local strain that is very hardy and is sold as William’s double yellow, though I’m not sure if the identification has been confirmed by experts. Anyway, I have this strain and used it as a pollen parent this summer with a good take rate. I put it one Sunsprite, Golden celebration, Jude the obscure and Graham Thomas, and have many fat hips developing on each bush. Don’t know about the ploidy but this WDY seems to be fertile. And it does produce plenty of op hips here.