Rosa moschata breeding options

In 2016 I obtained a plant of Rosa moschata, and I believe it’s ultimate source was from Peter Beales. Although I mulched the shrub heavily in the fall, I was surprised it winter killed to ground level. No sign of stem survival in the spring, so I thought I had lost it. But it did survive and grew quite well. My second surprise is this species has the ability to flower on new wood, which began a few days ago. This flowering trait, it seems to me, opens up some breeding options unavailable if this species only flowered on old wood.

My original plan using Rosa moschata in a breeding program was to combine it with Rosa woodsii, and then perhaps combining this species hybrid with Rugosas. The objective is to develop a shrub having very fragrant flowers and an attractive form similar to the Hybrid Musk cultivars, which show the influence of Rosa multiflora in their pedigree. In my opinion, it’s been a travesty that major rose breeding programs have concentrated on flower development and not also focusing on the shrub’s architecture. Roses could have been much more valuable to the nursery/landscape industry if this had been done, not to mention having significantly added to the attractiveness of landscapes.

I have have some Rosa arkansana pollen on hand, so I will cross Rosa moschata with this species and see where this takes me if I’m successful in developing seeds that germinate. If I develop this species hybrid, I could use it (if it’s fertile) again with Rugosas. Is the development of very fragrant, at least crown hardy (Zone 3) Rugosas having an attractive form, which flower consistently on new wood possible going this route? A key factor is how well Rosa arkansana will combine with Rosa moschata and ultimately with Rosa rugosa to develop progeny flowering on new wood, I would think. Of course, it’s worked well in this respect in the development of the Parkland roses.

Yes I know; some Rugosas flower on new wood. ‘Hansa’, for example.

As far as I know, no new Damask roses have been introduced by repeating the crosses (Rosa moschata x R. gallica) x Rosa fedtschenkoana that led to their development, and I wonder why not. Different Gallica cultivars could be used, which could influence the fragrance and the volatile oil content of the flowers. However, instead of Rosa fedtschenkoana I’m inclined to use Rosa laxa to improve cold hardiness, keeping in mind the disagreeable fragrance of its flowers to some people makes it problematic to use.

Very interesting idea, Paul. I wouldn’t worry about Laxa’s objectionable scent. It should be modified easily by the other scents involved and you may just create something rather unusual and possibly even better than what there is currently available. Go for it!

I have ingredients to make a new Damask, but here the Gallicas don’t bloom at the same time as my R. moschata, which seems to need to have some minimum amount of “heat units” met before setting buds. I’m guessing the original hybrid occurred in a warmer climate, where R. moschata got started much earlier in the season and coincided with the Gallicas. I tried freezing Gallica pollen last year and putting it on R. moschata when it opened, but I didn’t get hips forming. I’m not sure if I did something wrong with the pollen due to my inexperience, but in any case, I thought of another way.

Last year I bought a few more “true” Damask Perpetuals with little or no apparent China blood. I already had ‘Indigo’, and ‘Rose du Roi – original’ – which Vintage Gardens propagated from a reversion of ‘Panache de Lyon’, and is rather obviously different from the Hybrid Perpetual “Rose du Roi” being sold by a few other nurseries now. I also had ‘Blanc de Vibert’, but that one is a fussy plant, and I’d rather not encourage those traits. Last year’s additions were ‘Marbree’, ‘Delambre’, and ‘Duchess of Portland’. This small group of roses came about as reblooming offspring of ‘Quatre Saisons’ with Gallicas, and have a very Gallica air to them – except they repeat-bloom sporadically through the summer, and then have a flush about 1/2 the heaviness of the Spring flush in Autumn.

I also added a few old repeat-blooming Mosses – ‘Mousseline’ (aka ‘Alfred de Dalmas’), ‘Salet’, and ‘Soupert et Notting’. I already had ‘Quatre Saisons Blanc Mousseaux’, but I have yet to see any repeat-bloom on that, and its habit is definitely Damask, not Gallica. The other Mosses are growing much like the Damask Perpetuals – the main difference I see is in degree of “thorniness”. So I think of the two groups as “Damask Perpetuals – Mossed and Un-Mossed”. And I’m thinking that they could function as proxies for Gallicas in remaking a Damask.

This year, I just watched to see how the new roses “behaved”. There is definitely bloom overlap with R. moschata – especially since last year I moved R. moschata to where it gets more sun and heat, and this year it started blooming by the end of June instead of the end of July. This was still after the Gallicas were finished, though. My garden fell behind due to a crazy work schedule at a new job, and getting it back on track didn’t leave me time to make a concerted effort at collecting pollen, but I did move the potted Damask Perpetuals and repeat-blooming Mosses to where they are surrounding R. moschata. From what I understand, R. moschata doesn’t self-set seed readily, so I’m hoping that whatever hips mature on it will be something other than selfs. And I’m guessing that hybrids with its neighbors will be rather obviously different from self-seedlings. So we’ll see. Next year I’ll be able to do it properly. And until I get something, R. fedtschenkoana is already sitting by waiting to have its way with the offspring. Mine has scattered blooms through the Summer, and a modest flush in Autumn – just like the Damask Perpetuals. I’m hoping this would be reinforced in my “remakes” since the Gallica component would be fulfilled by Gallica-like repeat-blooming Damask Perpetuals and Mosses, and I’ll eventually get a repeat-blooming Damask.

I’ve never seen R. laxa, but I wonder if its “disagreeable fragrance” is anything like the linseed-oil scent I get from R. fedtschenkoana. It may seem odd how that scent contributed to what we call “classic Damask scent”, but I had a bit of an epiphany about it last year. I was dead-heading ‘Quatre Saisons’ (the pink Damask, not the mossy white sport of it), and I caught a whiff of clove. It was in my hand – a bloom whose petals had dropped prematurely after a rain still had fresh stamens, and they were clove-scented, just like R. moschata. I think that’s the “sharp” or “spice” top-note element of the scent in Damasks. The “middle” of the scent is Gallica, and I think the linseed-oil scent of R. fedtschenkoana is like the mortar binding it together, like a fixative. In the world of fragrances, fixatives often have “disagreeable fragrances” on their own – have you ever smelled true, pure civet musk, for example? But a dash of it provides a base for light and sharp notes added from elsewhere. I think the “classic Damask scent” is similarly built – fixative from R. fedtschenkoana, floral from R. gallica, and sharp spice notes from R. moschata.

BTW, where do you garden? If you are experiencing issues with R. moschata getting through your Winters, are you able to keep it potted and bring it somewhere inside for Winter? I’ve also found that it will rebound and bloom after being cut back hard, but also that it will get going earlier if it gets heat. If you can keep it in a black resin barrel planter – Home Depot sells them for about $20, and they’re nearly two feet in diameter at the top – its roots will heat up faster in Spring than if it was planted in the ground. That also means a longer time for its hips to ripen.




Thanks very much for your lengthy reply.

Your work developing a repeat flowering Damask is most interesting, and I have no doubt you will eventually do it.

Your theory about the development of Damask rose fragrance makes sense. What I call the “disagreeable fragrance” of Rosa laxa is likely the linseed oil scent of Rosa fedtschenkoana, which makes sense since I believe these two species are closely related.

The only Gallica pollen I have on hand is ‘Scharlachglut’, but I don’t think it’s appropriate to use with Rosa moschata because of the complexity of its pedigree. However, I have Rugosa pollen and so this morning I crossed Rosa moschata with ‘Hansa’. Doing this it made me realize that combining Rosa moschata with R. rugosa perhaps has more potential for success in my cold climate (Zone 3) than using Gallica cultivars. Of course, using ‘Hansa’ I’m also combining two roses having a clove fragrance and that can only be a good thing.

I also crossed my ‘Keewatin’, having semi-double white flowers, with Rosa moschata, using the former as the pistillate parent. ‘Keewatin’ has the longest continuous bloom of any Rugosa with the exception of ‘Schneezwerg’ and possibly ‘Jens Munk’. Of course, ‘Keewatin’ and ‘Jens Munk’ are related to ‘Schneezwerg’.

I’ll dig up my Rosa moschata (it’s only a small shrub) and store it in the fridge over the winter and then pot it up in late winter or early spring. That way, of course, I can get a much earlier start with it and likely produce a lot more flowers during its growing time.

I’m very excited about using Rosa moschata in breeding programs. A lot to learn, of course, and I’ll keep people informed of my progress.

Maybe you want to have a look at the website if Lens roses. Louis Lens used to do a lot of work with musk hybrids during the former century. A lot of his breedings are still sold at Lens Roses,from=homepage,language=E