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.[7]
Rose propagating methods have changed over the years, from the simple own-root varieties of the Victorian era, and progressing to the budded hybrids of the 20th century with its many options of exotic understock such as Rosa multiflora, Dr. Huey, Manettii, and Fortuniana. Now, rumor has it that many of the modern hybridizers and commercial growers are interested in returning to the simplicity of yore. Today's commercial rose growers are finding that budded roses are just too labor-intensive and expensive to produce. Because of this, it appears that we can look forward to more own-root roses being introduced and sold at our local nurseries in the future. Own-root roses will eliminate suckering and hopefully will eventually help to eradicate mosaic virus.
I would definitely mix in some compost with your garden soil as this will improve the structure of it. The dusting with fungicide is useful as it prevents the risk of infection, however, if you keep an eye on them and be ready to spring into action then it could be worth trying without . As for planting, I would personally keep them inside for a while, give them a chance to strengthen up before putting them outside in the elements!
Put the rose cuttings directly into water. It’s very important for the rose cuttings to stay hydrated so that they don’t dry out before you plant them. Immediately after you take the rose cuttings, put them in a cup of room temperature water until you’re ready to transfer them. Ideally, you’ll be ready to put them into the soil right after you cut the stems.[3]

Label the canisters with the name of the pollen parent. Do not put a lid on the canister so they will dry out and not get moldy. After a few hours (on some rose varieties), or the next day (on other varieties), the pollen sacs will burst open, thereby releasing the pollen. Sometimes you will need to shake the canister so that the rose pollen will release from the pollen sacs. The black film canisters make it easy for you to see the pollen, which looks like a fine yellow powder. The pollen will stay fresh for about two weeks.   
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.
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.

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.

Take a sterile Q-Tip or small sable artist's brush, and dip it into the rose pollen you want to use. Then dab the pollen-coated Q-Tip or brush onto the stigma of the rose you have selected as the seed (female) parent. You could also simply use your finger to apply the pollen to the rose. Repeat this procedure after four hours, and then again after another four hours. Label the rose hip with the name of the seed parent as well as the pollen parent, i.e. Fairhope x Miss Flippins. The name that appears first is always the seed parent (the mother), and the second name is the pollen parent (the father).   
The next step when you grow roses from cuttings is to use a pencil or metal probe push down into the planting site soil to make a hole that is deep enough to plant the cutting up to about 50 percent of its overall length. Place the cutting that has been dipped into the rooting hormone into this hole. Lightly push the soil in around the cutting to finish the planting. Do the same thing for each cutting keeping them at least eight inches apart. Label each row of rose cuttings with the name of the mother rose bush it was taken from.

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.[3] 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.[4]
Pests and diseases: Prevention is the best way to avoid pest and disease problems. Start with disease-resistant varieties, keep plants in healthy condition (well fertilized and well watered), maintain good air circulation, keep foliage dry, and remove any diseased foliage or spent flowers. For Japanese beetle grubs, use beneficial nematodes or Milky Spore (Bacillus popilliae). Rose Rx is effective against scale, spidermites and aphids. For more information, see the Pest and Disease Finder.