Roses can reproduce both asexually and sexually. Asexual reproduction does not use seeds and generates exact duplicates, or clones, of the parent rose. If you want to create new varieties of roses, you must grow them from seeds instead of utilizing asexual reproduction methods.
Types of Roses
The method of asexual reproduction to use will differ depending upon the type of rose. According to the article "How Do I Propagate Roses?" in the Ultimate Resource and Learning Center, old roses, English roses and miniatures are the best candidates for softwood rooting because they grow vigorously on their own roots. You can also use hybrid teas and floribundas.
Methods of Asexual Reproduction
There are three methods of asexual reproduction of roses: softwood rooting, hardwood rooting and bud grafting. Rooting refers to cutting a cane of an existing rose and replanting it. Hardwood and softwood rooting are similar processes; according to rosemagazine.com, the only difference is that softwood cuttings are made from shoots that are still green and are kept indoors until they mature. Bud grafting refers to a process in which you cut a bud off a rose bush and insert it into the stem of the rose you want to reproduce.
To reproduce roses via hardwood rooting, you must begin in late summer or early autumn. Rosemagazine.com says to cut off a cane from an existing rose that is 1 to 2 feet in length. Remove the leaves, twigs and thorns and cut the cane into pieces 6 to 9 inches in length.
Prepare a rooting hormone solution by soaking cut up willow twigs in water overnight. Place the cuttings in the willow water the next day and let them sit overnight.
Once the cuttings have soaked, plant each one in a separate pot filled with potting soil. At least two-thirds of the cutting should be under the soil. Spray the cuttings with water. Place plastic bags over the cuttings and put them outside. They must be shielded from direct sunlight. Over the next month, check the pot once every few days to make sure the cuttings are moist and spray with water as needed. The cuttings will take root within a month.
Rosemagazine.com says that softwood rooting is similar to hardwood rooting, but you should use a green side shoot and trim off all soft growth when preparing the cutting. You should also keep the cuttings indoors until winter is over to ensure they are not exposed to frost. The Ultimate Learning and Resource Center suggests planting your cuttings in plastic bags and transferring them to pots only after the roots have begun to grow.
Commercial roses are created by grafting buds onto existing roses. Love-of-Roses.com provides a method for doing this yourself. First, cut a green shoot off the rose bush as you would when softwood rooting roses. Soak the cutting in water overnight. Then cut the buds off the shoot with a sharp knife.
Make a T-shaped cut in the rose to which you are grafting. The top of the T and the base of the T should both be approximately 1 inch long. This cut creates flaps on the stem of the rose; when you peel them back you should see a slimy, green layer, If you have cut into the green layer, you have cut too deeply.
Pop the bud into the cut and bind it with grafting tape or twist ties. Monitor it to make sure roots don't form on the outside of the rose stem.