I've grown and seen quite a lot of roses own-root and grafted, over a lot of years, and my answer would be a fairly firm "no." Plant age may have something to do with it, or some aspect of microclimate. Also, I'd think that if it were true, the rose-show crowd would be very keen on certain stocks for the color they produce, and that concept is never even discussed, afaik.

Thanks, Dr. Manners. I didn't really think it did, but I have no explanation for the color variation--well, maybe age, because the grafted rose is about five years old. It will be interesting to see if the "children" of the grafted bush darken with age.

I would venture a different opinion on the matter. From what I have seen, different rootstocks are of different sensitivities to soil conditions such as pH, mineral content, and whatever other conditions can be present. The variety of rose may be a key to the question. I have seen the HT Silver Jubilee in the same garden on 4 different rootstocks, and they did show significant differences in flower color. The plant characteristics such as foliage and growth habit were all fairly consistent. The difference was in the way the rootstock was picking up the micronutrients. I suspect the focus was on available iron because of the way the colors developed. So, yes, I do see that there can be differences between roses of the same variety on different rootstocks, but it might be dependent on the inherent color of that variety.

Dr. J. H. Nicholas in A Rose Odyssey stated they do affect color. My experience has been that due to the hatred multiflora has for the alkaline soil and water in the south west, colors vary greatly, particularly in the violet toned roses which can be literally white on chartreuse foliage here on multiflora, and a number of the violets own root.

I feel almost sacrilegious suggesting that Dr. Manners may not be perfectly correct in everything regarding roses. But Gerd Kruessman, in his book 'Roses' that I used to have, discusses the pros and cons of various rootstocks, among other things the effects different rootstocks have on the intensity of bloom color. I bring it up for what it's worth.
Melissa

Well, that's interesting, everyone. If it does affect color, I don't find her quite so beautiful own-root as she is on Fortuniana.

I forgot to say where the third cutting-grown rose is. It's still in a pot and also displays the lighter color. Boo-hoo. I really need to learn how to graft onto Fortuniana. It's not like Dr. Manners hasn't tried. He handed out detailed instructions at a rose meeting I attended. I'm too chicken to try it.

Thank you, everyone, for your differing opinions.

Perhaps one rootstock simply provides more nutrients to the scion--wouldn't that be enough to tweek the color a bit?

A strong-growing rose has a better color, or resists fading more, than a weak baby, at least in this garden.

I've found that both age and rootstock have affected color on some of my roses. I have several purple roses that have grown darker and more richly colored as they've gotten older. I also have three Bernstein-Rose (Tantau) roses, two on multiflora and one on Dr.Huey. In my alkaline soil, the Huey grafted rose is more vigorous, floriferous and with blooms of deeper, richer color than those of the multiflora grafted roses. Diane

Ok I had not considered an observation above -- if the root system used makes the plant healthy vs. unhealthy (e.g., multiflora on alkaline soil), then, yes, there could be an effect, but it is not really a direct effect of the rootstock; rather, it's a sick plant. We never use multiflora, since it dies here very quickly.

On the other hand, on our campus, 'Mrs. B. R. Cant' on its own roots, 'Dr. Huey', and 'Fortuniana', seems to be in the same color range regardless of those root systems. Of course it is a variable rose, flower to flower, on the same bush.

I don't think my two Bernstein-Rose plants on multifora are sick; they bloom well, and have healthy leaves--they just aren't as big or produce as richly colored blooms as the B-R on Huey. I certainly am not going to remove them. Since I plant the bud union well below grade, for all I know, those two plants have gone own root. Diane

Verrrry interesting. Thanks for all your responses. I had to prune my Fortuniana Mrs. BRC radically due to a fungal cane dieback problem I had in my garden. She's very odd looking now, because the old canes were wrist-sized or larger. She looks kind of like a french poodle with poofs of leaves at the end of those huge canes. I don't know if it will recover and begin to look more normal. I guess if I have to replace her, it will have to be one on Fortuniana to keep the deeper color.

I cannot add personal observation to this discussion, but I would note that Kordes in explaining the color variations of 'Orange Triumph' said in a letter to McFarland (reprinted in one of the late thirty ARS's) that the rose showed an orange color when budded to canina, but a red one when budded to multiflora. The two rootstocks were common, respectively, in Europe and the US at that time.
FWIW, JimD

She looks kind of like a french poodle with poofs of leaves at the end of those huge canes.

Don't worry about the old girl, she'll bounce back and quicker than you think. There's good reason she's been around for a hundred and ten years.