I have zero germination on R. acicularis. Relatively tons of seed. Before posting on here I googled it and came up with the following from the Alaska Rose Society:
For wild rose, Rosa acicularis, seeds require a two-month period of warm stratification followed by three months of cold stratification for complete germination. The extracted, dried seeds can be mixed with sand or vermiculite as outlined above or sown into flats of sterilized potting soil. Keep the flats or bags at room temperature (approx. 21° C, 70° F) for two months of warm stratification. NEVER ALLOW THE SEEDS TO DRY OUT! Move the flats or bags to a cold root cellar or refrigerator (4° C, 40° F) for 3 months of cold stratification. Return the flats to warm temperatures or remove the seeds from the sand or vermiculite and sow in flats of potting soil. Seeds begin to germinate within 2 weeks. If not enough seeds have germinated after 30 days, try repeating the cold stratification for 30 days, and return to warm temperatures. Repeat the cold/warm cycle until most seeds germinate.
So it appears that R. acicularis requires significant warm stratification before the cold stratification. I made some outdoor seed beds last year, seeded just before frost, and none of the R. acicularis germinated then either.
I am also having very poor germination on R. nitida, so I’m suspecting that it, too, might require warm stratification prior to the cold.
The northern roses that I work with, require that not so much the seed not be dry but that the hip should be fully red but still hard to the touch and defiantly not mushy. My results are not the best, 50-80% germination, but after the hips are dry like when I have collect in late fall there is no hope for me. Usually the mice and or moose get them anyways.
The CassiorhodonI work with from the wild are mostly Rosa woodsii, R. pisocarpa, R. blanda. Johannes
Johannes maybe the American species roses have evolved to being eaten by moose, bears and other critters , digested and attacked by gut enzymes to be excreted out in their little fertilizer packages and then germinate in the Spring.
R. nitida does seem to benefit from warm strat. from my experience. R. arkansana seems to highly benefit from it too. I did a study years ago looking at the short term impact of drying of seeds. It varied between roses, but the take home message I learned from what I did was that drying either didn’t matter or it hurt, so I avoid drying seed if don’t have to do it. For warm strat. I typically have the seeds in moist peat for a couple months at room temp. before the cold treatment.
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.