Just as with many other shrubs, roses can be grown from cuttings. It’s not a fast process – it may take a couple of years before your new plant produces flowers. But if you have a favourite rose, it can be fun to try. The cuttings need to be taken fresh from a healthy plant – don’t try to grow a new rose bush from the bunch of cut flowers you have sitting in a vase. And as roses bushes are pruned during winter, this is the most convenient time to take and pot up your rose cuttings.
While your cuttings take root, keep them covered and moist. In a garden bed, a simple DIY mini greenhouse does the trick. Just place a bell jar, a garden cloche or an overturned mason jar over the cutting. A clear plastic bottle with the bottom cut out and the cap removed works, too. Water the soil regularly to keep it moist, but not soggy. Your mini hothouse will keep the humidity high inside.
Plant the seeds. Some store-bought seeds can be planted immediately. If you germinated your own seeds as described above, plant them as soon as they begin to sprout. Plant with the sprout pointed downward, as this is the root. Lightly cover them with soil, about 1/4 inch (6 mm) deep. Space seeds at least 2 inches (5 cm) apart to minimize competition.[5]
Despite their reputation for being finicky, most roses are simple to grow and easy to propagate at home. “Propagate" simply means to reproduce a plant easily from a simple cutting. Unlike seeds, which produce very different plants, rooted cuttings produce replicas of their parent. You don't have to be a trained rosarian to reproduce treasured family heirlooms or favorite garden roses.
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
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.
Pruning: Dead, weak and sickly stems can lead to disease problems. Pruning these away will increase air circulation to the center of the plant and minimize fungus problems. Pruning also stimulates new growth, and allows you to shape the plant in a pleasing manner. Spent flowers should be removed during the growing season to encourage reblooming. Use a scissor-action pruner for the cleanest cuts.
The ripened rose hip is then placed on a clean cutting board and cut in half to remove the seeds. Place the seeds in a clean container. Add some diluted bleach to kill off any bacteria and fungus spores. You can make the bleach by mixing drinking water with two teaspoons of household bleach. Stir the seeds well before rinsing them and using bottled water to remove all the bleach. To further clean and disinfect the seeds, put them in the container and add some hydrogen peroxide. The seeds can be soaked for up to 24 hours before rinsing them with clean water to clear all the hydrogen peroxide.

I received some seeds as birthday present, the seller included a bonus packet of rose seeds. There’s no indication if they’ve been stratified. If I stratify them now, it will be July when they’re ready to plant. In this region (I’m ~50 miles north of Portland, Oregon)it might be mild or very hot. I’ve read that rose seed won’t sprout if it’s too hot – how well do rose seeds keep? Will they still be viable next Spring, or should i take a chance on the weather and start them now?