After the rose seeds have soaked overnight, rinse them in a strainer and place them into the blender with at least a cup of plain purified water (making sure all seeds are covered), and turn it on for a few minutes. It usually doesn't chop up the seeds, but rather, it will clean off the pulp remaining from the rose hip, which would otherwise mold if left on the rose seed. You may see a few seeds chopped up, but those usually aren't viable anyway. Flush the rose seeds again through a strainer using fresh purified water.
Soaking the seeds is a crucial step if your seeds will germinate properly and stay clear of any diseases. You MUST not mix the bleach with the hydrogen peroxide as this results in a chemical reaction. 3% peroxide for 24 hours is just fine. This is also a good time to perform the water float test. Remove all seeds that float as they might not be viable.
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.
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.
To get the best success, yor rose seed will need a period of stratification (a cold period of about 6-12 weeks). Its a good idea to time this so that it coincides with when they would naturally start to grow in spring – probably around early March, depending on weather conditions. I would look to sowing them in late November/ December and popping them outdoors or if we have a mild winter then stick them in the fridge!
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.
One way to stratify the rose seeds is to place the cleaned seeds on a paper towel (a heavyweight brand such as Bounty). Then moisten the paper towel with a solution of half & half purified water and peroxide (to help prevent mold). Fold the paper towel closed, encasing all the rose seeds in the moistened paper towel. Then place the towel full of seeds into a plastic zippered bag. Mark the seed variety and date on the outside of the plastic bag with a permanent marker, and then place the bag into the refrigerator set at about 34-38 degrees. Never freeze the seeds, and do not let them dry out. The moistened paper towel should remain moist in the closed plastic bag for many weeks.
Remove the seeds from the fridge. Try to do this around the time that the seeds would normally start to germinate, such as in early spring. Make sure that the environment outside of the fridge is about 70 degrees Fahrenheit. The seed will not sprout until you take them out of the fridge. Depending on the rose variety and individual seeds, the seeds could take anywhere from four to sixteen weeks to germinate. Often, 70% or more of the seeds never sprout at all.
Everybody has a story to tell of how their grandma would stick a piece of rose stem into the ground and then place a Mason Jar over the stem to make it grow. There are tales of how the early American settlers of the 1800's traveled to the far reaches of the wild west in covered wagons, with grandma bringing along "starts" of her favorite roses from back home. Perhaps the treasures of these "monsters on wooden wheels" were raided, and they discovered the Yellow Rose of Texas hiding under the bonnets of the women. Or maybe the settlers used their precious "starts" to barter for provisions along the endless dusty trails.