Water. Irrigate roses deeply but infrequently, applying water directly to soil using soaker hoses or drip irrigation. Water needs vary based on weather and soil, so check soil with your finger. Water often enough to create consistently moist soil – not overly wet, not bone-dry. To prevent diseases, keep foliage dry, especially if you must water late in the day.
The easiest way to begin experimenting with rose hybridizing, especially for the beginner, is to simply let some of your roses self-pollinate themselves, so they will "go to seed" and set hips. I have found that Playboy, Hurdy Gurdy, Peggy T and Fairhope are some of the easiest roses to set hips, and there are many others. Let the rose hips stay on the rose bushes at least four months before harvesting.
I too, have tried the cut rose flower method, but haven't yet been successful--perhaps because there are chemical additives that the roses have soaked up, or because there are no nodes (which are the points where new shoots grow out), or because the stems have spent much of their energy producing the flowers...BUT, perhaps if the flowers were immediately cut off and some rooting hormones applied to the bottom cut ends, that may work.
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.
There will be disappointments along the way, when many rose seeds fail to germinate, or perhaps they do germinate, only to die several weeks later from damp-off disease. Sometimes a rose seedling will turn out to be as ugly as sin, or very sickly, and you will reluctantly have to throw it away. Other times they will be just ho-hum, or look too much like its parent, and therefore have no value. But, just when you don't expect it, you might discover that one of your rose seedlings turns out to be very special.
Growing roses from seed can be challenging, since the majority of seeds you collect often won't germinate regardless of your efforts. Fortunately, most rose plants produce a large quantity of seeds inside their rose hips, so it usually isn't necessary to achieve a high success rate. Keep in mind that the plants that grow may be different in appearance or other characteristics from the mother plant, especially if that plant is a hybrid of two varieties grafted together.
I am curious... it seems that you are just supposed to "soak" the cut stems for a week or more in water.... which is mostly what people normally do with cut roses. But whenever I put roses my boyfriend brings me in water, they just fade within a week or so. I'll "feed" the roses with either sugar in the water or with the packet of plant food that comes with them. I'll cut off a small bit at an angle from the bottom of the stem evert day or so. But after a week or so they start wilting and drooping, so at that point I just take them out and hang them upside down to dry.
Cover the cutting loosely, pot and all, with a plastic bag or plastic wrap and keep the soil moist. Putting a tall stake into the pot will hold the plastic away from the leaves. If the plastic touches the leaves, they remain wet and can succumb to a fungus disease. Along the same lines, make sure the condensation can escape from the plastic or the stem will rot.
Fertilize the roses. After they are established, roses should be fertilized a few times per growing season. Use fertilizer (either liquid or granule) in early spring, when you see the first few leaves sprout. Use it again after the first bloom, and again if there's another bloom. Stop fertilizing the roses at the end of the summer, just before Labor Day.
Prepare a pot. Fill the small pot with potting soil. For the best results, replace a quarter of the soil with perlite, peat moss, or vermiculite, or a combination thereof. This will increase air flow and draining, giving your cutting a better opportunity to root. If the soil is dry, water it and allow the excess water to drain out, so that the soil is evenly moist.
A gentle way to clean the rose seeds is to use a Cuisinart or other brand of blender with a dough blending attachment, which is made of plastic and does not have sharp blades. You can blend the rose seeds using this gentle dough attachment for several minutes without any damage to the seeds. Do not use a blender with sharp metal blades as damage to the rose seeds may occur.
When pruning, be judicious. If you prune too hard in autumn, plants can be damaged beyond recovery. Instead, wait until spring, when plants begin to leaf out for the new season. (Roses are often not the earliest plants in the garden to respond to spring’s warming temperatures, so be patient.) Give the plant time to show its leaf buds then prune above that level.