As is often the case, first we have to unlearn. Hybrid Musk’ roses actually have no proven connection with ‘R. Moschata,’ the “Musk Rose”. The Hybrid Musk class is based upon the Hybrid Multiflora, ‘Aglaia,’which resulted from a cross of R. Multiflora with ‘Reve d’Or.’ The latter has been classed as a Noisette since its introduction in 1869. All that is known of its origin for certain is it is a seedling of ‘Mme. Schultz,’ which was presumed to be a Noisette, though nothing is known for sure of her origin. As early as 1857, in The ScottishGardener; a magazine of horticulture and floriculture, ‘Mme. Schultz’ was described as being “in the way of Lamarque”, meaning she resembled what had become accepted as Noisettes, a cross between Moschata and China Roses. If we presume ‘Mme. Schultz’ was half Moschata (Musk), then ‘Reve d’Or’ was at most half Musk.’ Aglaia’ would then be one-quarter (at most) Musk and one half Multiflora, and has always been classed as a Hybrid Multiflora. Hybrid Musk roses, then, are primarily Hybrid Multifloras. They could be viewed in terms of being smaller, repeat flowering Multiflora Ramblers.
R. Multiflora is basically a climbing plant. From observation of the many self-seedlings and known hybrids, it carries dwarf, repeat flowering genes which can be expressed when the right combinations are made. “The Fairy Roses”, “Baby Roses” or R. Multiflora perpetual nana, which have long been sold as seed, are examples of dwarf, repeat flowering seedlings from it, and are classed as Hybrid Multiflora. Though they often resemble “The Gift”, which is classed as a Polyantha, they remain Hybrid Multiflora.
‘Mignonette’ and ‘Pacquerette’ are generally considered the first of the new breed of roses called Polyanthas. They resulted from crosses between R. Multiflora and China Roses. These roses created quite a sensation when first introduced. Quickly, many breeders were raising self-seedlings from them or crossing them with Teas, Hybrid Perpetuals, other Multiflora ramblers and Hybrid Multifloras to raise new additions to the polyantha class.
The German hybridizer, Peter Lambert crossed ‘Aglaia’ (Hybrid Multiflora) with the Hybrid Perpetual, ‘Mrs. R. G. Sharman-Crawford’ to create ‘Trier’ (Hybrid Multiflora). Suddenly, crosses of the Hybrid Multiflora “Trier” with Hybrid Teas, Hybrid Perpetuals, Teas and Floribundas, began creating Hybrid Musk roses. But, remember, ‘Trier’ is presumed to be, at most, one-eighth Musk, and known to be one-quarter Multiflora.
Most Hybrid Musks of known parentage arose from either crosses with Trier or direct crosses with R. Multiflora through ‘Ballerina’, which is virtually pure Multiflora. Peter Lambert’s Hybrid Multiflora, ‘Trier,’ was quite busy at the same time. Not only Lambert, but many others were busily crossing Trier with all manner of roses from R. Foetida, Teas, Hybrid Perpetuals to other Polyantha seedlings raising more polyanthas and a new class of roses named "Lambertianas," to honor Lambert and to describe roses that seemed to have something in common. These Lambertiana roses were basically more vigorous semi-climbing to climbing polyanthas. Shorter growing than the traditional Hybrid Multiflora rambler, and with repeat flowering, these roses were the bridge between the Hybrid Multiflora and Polyantha classes. In many ways, they could be considered Climbing Polyanthas.
Polyanthas continued being developed toward bushier, more densely flowering plants with increasingly larger individual flowers. Crosses with Teas, Hybrid Perpetuals and Hybrid Teas reduced the cluster sizes, but increased the size of the flowers until the introduction of the Hybrid Polyantha class, later called Floribundas. As the class developed, cluster size reduced and individual flower size increased similarly to the development in the Polyantha class. Often, the same roses were crossed with the Multiflora hybrids to create both types.
Lambertianas were less vigorous “Hybrid Musks” with generally smaller flowers, but still semi-climbing to climbing habit and repeat flowering. Polyanthas are dwarf, repeat to continuous flowering hybrids of the same roses which created Hybrid Musks and “Lambertianas”.
As was previously mentioned, R. Multiflora is a climbing type plant. Like most roses, it can mutate or sport, often to climbing forms. Climbing sports of Polyanthas often resemble repeat flowering Multiflora Ramblers, Lambertianas, even Hybrid Musks, as well they should. They all contain strong Multiflora influences, massaged by China, Tea, Hybrid Perpetual and Hybrid Tea genes. For all intents and purposes, they’re all Hybrid Multifloras. Attempts to “classify” them have predominantly been based on, “if it quacks like a duck…” Even though they all are strongly genetically related, if one “looks” as if we expect a polyantha to appear, we consider it a polyantha. The same holds true for the other two “types”, even though they are all Multiflora hybrids.