Rose seeds need to go through stratification (an artificial cold spell) for 10 to 12 weeks before they will sprout. This, combined with a germination success rate of 20-30% makes propagation by seed an unattractive prospect. on by seed an unattractive prospect. If you still want to try it, find a good source of information that will guide you through the process.
Label the canisters with the name of the pollen parent. Do not put a lid on the canister so they will dry out and not get moldy. After a few hours (on some rose varieties), or the next day (on other varieties), the pollen sacs will burst open, thereby releasing the pollen. Sometimes you will need to shake the canister so that the rose pollen will release from the pollen sacs. The black film canisters make it easy for you to see the pollen, which looks like a fine yellow powder. The pollen will stay fresh for about two weeks.
Rose propagating methods have changed over the years, from the simple own-root varieties of the Victorian era, and progressing to the budded hybrids of the 20th century with its many options of exotic understock such as Rosa multiflora, Dr. Huey, Manettii, and Fortuniana. Now, rumor has it that many of the modern hybridizers and commercial growers are interested in returning to the simplicity of yore. Today's commercial rose growers are finding that budded roses are just too labor-intensive and expensive to produce. Because of this, it appears that we can look forward to more own-root roses being introduced and sold at our local nurseries in the future. Own-root roses will eliminate suckering and hopefully will eventually help to eradicate mosaic virus.
You may even wish to cut your cuttings down to 3" to 4" and double your plants, but they will be more prone to rot or dry up faster if you let the soil dry too long. The cuttings that are 6" to 8" seem to do much better, and if cuttings are even longer, the water has a longer length to travel up and down, and the cutting may end up more dehyrated with the upper part dying off. So 6" to 8" is a happy medium.
The Baggie Method: This was the first method I ever tried. Here you fill 2-inch plastic pots with potting soil, insert the rose stem halfway inside the pot, then put the pots into a one-gallon plastic zip-lock bag. You can get four 2-inch pots into each gallon bag. I didn't like this method because it caused many of the cuttings to rot since the bags tended to fold over and therefore prevented the air from circulating. The success rate of this method is not very good. It may be helpful to place a couple of small sticks inside the bag to help keep it upright and full of air.
Español: cultivar rosas usando semillas, Italiano: Coltivare le Rose Usando i Semi, Português: Cultivar Rosas a Partir da Semente, Русский: вырастить розы из семян, 中文: 用种子种玫瑰, Deutsch: Aus Samenkörnern Rosen ziehen, Français: faire pousser des roses à partir de graines, Nederlands: Rozen kweken uit zaad, Bahasa Indonesia: Menanam Bunga Mawar dari Biji, العربية: زراعة الورود من البذرة, Tiếng Việt: Trồng hoa hồng từ hạt, 日本語: バラを種から育てる, 한국어: 씨앗으로 장미 기르는 방법