From ancient times double flowers have been found in allmost every decorative plant species and favored as it is with a few exception the shorter way to increased flower durability by lengthening the “pre anthesis” phase (that’s delaying the maturity of sexual organs).
Single flowered vars and species have a charm of their own the heavier petaled may lack but if never disapearing had a smaller market share. They were long rose for connoisseurs.
This small market share expanded rather recently as a new large market for public or collective plantings was found for the newer shrub and ground cover roses.
From the beginnings these new vars were bred combining deliberately the selected over two centuries lasting petals and bright colors of modern roses with the strength plus desease resistance of species and close to species vars.
This is quite obvious if one consider the known contribution of Picasso (stronger petal and bright color) to many Mediland roses. A contribution that is bigger than declared. It made old Sam McGredy angry against Alain Meilland.
Same for Noaks vars that mostly derive from Immensee a wichuraiana derivative crossed with different Floribundas.
Acceptability of single flowers is growing higher than ever as public is now used to considering single roses beauty. Not long ago the general public did not consider them as “roses”.
I don’t have a lot of singles, which is a shame because I love them. Most the singles I have are species or near species. There are only threee non-species singles here; ‘Nozomi’, ‘Altissimo’ (which I spose isn’t technically a single but is close enough I reckon in this case), and ‘Anne Endt’. The species ones inlcude R. laevigata (+ anemone), R. wichuraiana, R. multiflora (two varieties), ‘Scabrosa’, R. mulliganii (I think… pending confirmation next summer when it flowers). (Bracteata and gigantea are on their way as is rubiginosa). Of these it seems pretty clear that flower longevity in these singles is proprtional to the petal thickness and petal size too. ‘Altissimo’ lasts pretty well on the bush and are big thick robust petals. ‘Nozomi’ lasts only a few days as does ‘Scabrosa’ and Anemone. R. laevigata seems to last only a week or so but has thicker petals than the previous two but it is still pretty thin and easily marked. The two types of multiflora flowers (one white and one pink) seem to last differently… the white not lasting as long as the pink which is slightly large and has slightly thicker petals. I used the pink multiflora with miniatures this year with some success and am looking forward to seeing what the seedlings turn out like and am hoping for miniature singles. ‘Nozomi’ has a tiny flower that is very thin and I would imagine these two factors combine to cause it to descicate very quickly in warm weather. ‘Scabrosa’ seems wafer thick and barely lasts two days before shrivelling up making it really hard to photograph because the flowers open quickly, have such a short life and are easily damaged by environmental factors such as wind that finding a good one can take some effort and/or intervention. I have one of the single dark red Noak ground cover roses that has not yet flowered for me (recently struck cutting) but after seeing it around it seems to have pretty thick petals that last pretty well. I would imagine these traits would be inherited quantitatively and could be selected for to increase the longevity of single flowers.
I got a remontant single out of Lilac Charm x R. webbiana var. nanothamnus.
I somewhat resembles a selfed seedling but in other ways it doesn’t. I don’t know what to think about it.
Early on I grew out a number of Lilac Charm x OP seedlings and none quite resemble this seedling. It seems to show signs of hybridity. It’s vigorous. The prickles are unusual and when I back crossed it onto ‘Riverbanks’ I got a white seedling.
Whatever it is, it’s seed fertile too.
I’d love to know if it’s a hybrid. The R. webbiana var. nanothamnus I got from Joan Monteith but I’ve since lost it. It was pink and didn’t fit the description for the species which makes me wonder if it could have been some type of hybrid or actually a different species?