I have successfully taken rose cuttings with both new and old wood. It is important to let the new stems sufficiently mature. The new wood is usually mature enough after the stem has just finished blooming. If you don't let the stem mature enough, then it usually becomes limp and will die before you can get it to root. I take cuttings from new rose stems in the spring right after the first bloom cycle. Then in early to late fall (in Southern California) I prefer to use more mature or old wood. When using old wood in the fall, I will remove the rose cuttings from the Mason jar, baggie, or mister, after only several weeks since it is cool enough then for them to root on their own as long as I water them daily.
When the rose hips are ripe, after about four months, cut them off the bush. Some rose hips will turn yellow, orange, or red, but others stay green even when they are ripe. You can open the hips as soon as harvested or you can store the unopened hips in the refrigerator for several weeks before opening. Then slice the rose hips in half, and open them with a knife. A butter knife will do just fine. Now, dig the rose seeds out of the rose hip with the knife, and throw away the pulp and outer shell.
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.
Northern gardeners need to know exactly what zone a rose is hardy to. Southern gardeners must also watch to see what zones are recommended for each particular variety, as some roses perform very poorly in hot and/or humid weather. Read the catalogs carefully and, if possible, purchase your roses from a local or regional grower. They will be able to advise you from experience about how a particular variety will perform in your area.
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 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.
Most softwood rose cuttings will root within 10 to 14 days.1 To test their progress, tug very gently on the cuttings. You'll feel a slight resistance as the new roots form and grow into the soil. A gentle fish- or kelp-based fertilizer during this time provides beneficial nutrients. Once roots are established and plants show strong new growth, you can transplant your new roses to more permanent garden homes.
Black Spot: Rose plant leaves with black spots that eventually turn yellow have black spot. This is often caused by water splashing on leaves, especially in rainy weather. Leaves may require a protective fungicide coating, which would start in the summer before leaf spots started until first frost. Thoroughly clean up debris in the fall, and prune out all diseased canes.