Rod, I’d never have suspected that R. bracteata is marginally sterile. Many years ago I harvested hips with 20-30 seeds from it. I’m not familiar with R. clinophylla.
Rod, I don’t know how to distinguish between bracteata and clinophylla…but the plant I purchased as R. bracteata is maybe not promiscuous but definitely not sterile. It never sets any open-pollinated hips and refuses many pollen parents that I’ve tried on it; but, it sets at least 20 or 30 seeds (like Peter’s experience), probably many more than that, from pollen of some other species and species hybrids. I’ve haven’t tried it much as a pollen parent, so I can’t comment on its fertility in that respect.
I haven’t seen much reference to it. Is clinophylla naturalized in the United States? I know bracteata is, even to the point of being considered somewhat of a weed.
That has clarified something for me - I wondered how Bracteata could naturalise anywhere if it was marginally sterile. ( Maybe I misread it? - the writer could have been referring to its hybrids? )
Would like to try Clinophylla though - supposed to be very tolerant of wet conditions.
Thanks for pointing me to a clue on how separate these two ( even if it was in front of me all the time - seed count )
I can’t locate my technical papers I have from a hybridizer in India. As I recall he was going after disease resistance and evergreen foliage. His comments were that they were obviously fairly closely related, but that the Bracteata was far superior in the disease resistance category, and he had a lot of difficulty going past the F1 stage with both
R. Bracteata and hybrids are difficult to work with, it does not cross easily and many of the hybrids are practically sterile or produce week seedlings.
Texas A& M found some hybrids (not bractatea hybrids) with unusual numbers of chromosomes,17 or 23 or 26 rather than the typical 14,21 or 28. When I heard that I immediately thought of R. Bracteata hybrids.
Ralph Moore has been presistant enough to produce a few fertile hybrids. Muriel and Pink Powerpuff helped lead the way to his new series, Tangerine Jewel, Star Dust, Precious Dreams, Precious Memories, and Star Dust.
Pearl Drift is also reported to be fertile.
R. Bracteata is reported to bloom intermittently all year and does not get blackspot.
If this link work it leads to a drawing or R. Bracteata.
R. Bracteata is reported on Help Me Find to be a much larger rose. I have seen R. Bracteata only once, but I remember it having the glossy leaves like Mermaid.
Memoirs, Horticultural Society of New York, vol 3 (1927)
Sterility Encountered in Rose Breeding
J. H. Nicolas
“Have the soil and original method of propagation a direct relation to the fertility or sterility of a plant? We have long noted here that grafted plants of R. Hugonis, for example, will profusely bear seeds, while plants grown from cuttings are very scant seed bearers, almost approaching sterility. Paul’s Scarlet Climber as an own root plant may be considered as sterile, but a grafted plant will bear both self- and hand-pollinated seeds. I have also noted that plants of the same variety in different parts of the nursery have a different seed bearing capacity, although both receive the same amount of sunshine. As an instance, R. bracteata and R. Altaica at one location are practically sterile, while a short distance away, but in a different soil, nearly every bloom, either hand- or self-pollinated, sets fruit.”
While b grows as a bigger plant, these roses are clearly related with similar brown felted fruit.
Leaf size is very different with distinctly bigger and less numerous leaflets for bracteata.
Spination differ with bracteata being hooked and very acute while clino has sparser straight longer spines.
Both quite fertile.
For me b is difficult to germinate
Know anyone who has a cow? You really need to borrow some cattle to eat the hips as a pretreatment for germination. The germination of bracteata after this treatment is legendary.
Peter,
Good stuff! I wonder what sort of animals eat Bracteata hips back in China.
Along similar lines, I am reminded of this:
Annual Report of the Minnesota State Hort. Soc. 19: 170 (1891)
Fruits in North Dakota
Prof. C. B. Waldron
Agricultural College, Fargo, ND
“The roses that grow the most abundant and fruitful are the Rosa blanda and the Rosa Engelmanni. The latter has a large fruit about two and one-half times long as broad, is rather juicy and of a flavor much like the thorn apple [Crataegus coccinea]. The rose hips of both species are eaten readily by the prairie chicken, grouse, antelope and rabbit, the indian also comes in for his share. I have seen this fruit in such quantities over large areas that it would have furnished food for hundreds of sheep.”
Several years back in the RHA newsletter I wrote and article titled “Cowpeat, anyone?” This was one of the two things driving my adventure into nitrate for germination. What happens to a cowpat when it weathers in the pasture? Nitrification of course, which results in high nitrate. And the seeds germinate like weeds down Texas way in response. Cowpeat is processed dairy cattle manure in which more of the N is lost, or converted to organic forms while giving a very high organic material. But I had very poor luck with our local composted manure as a germination stimulant. So a cowpat is not the same as cowpeat.
In a letter published in 1820 quoted Willdenow’s Principles of Botany and Vegetable Philosophy (1811):
“Besides oxygen, ammonia favours the germination of seeds: hence, they germinate almost immediately, when placed in dung, which, therefore, serves as manure. Cow-dung, we know, consists of muriatic acid and ammonia. In fluids which contain no oxygen, seeds will not germinate. Thus, they never germinate in oil, which consists of hydrogen and carbon.” http://bulbnrose.x10.mx/Heredity/HSNAcidAmmonia1820.html
When seeds pass through an animal’s digestive tract, the seed coats are softened (at least) by the acid and stimulated by the ammonia. When their journey ends on the ground, oxygen soon reaches them as the dung dries and cracks.
Fermentation accomplishes much the same thing, if the fruit has moisture and sugar. Azobacteria feed on the sugar and “fix” atmospheric nitrogen for their own use. The excess nitrogen is excreted as ammonia. Some of the sugar is fermented by yeast, and then acetic acid bacteria convert the ethanol to acetic acid.
John Cook (the creator of ‘Radiance’) wrote:
“When perfectly ripe, bruise the heps, or seed balls, and put them in sand. They will soon rot, when you can wash the seed out and sow it at once. It will take from three to ten months for any to come up.” http://bulbnrose.x10.mx/Roses/breeding/CookRoses1907.html