Be aware of your variety’s needs. Rose care will depend a lot on the variety you’re raising. Some roses like William Baffin and Lady Hillingdon climbing roses are more drought tolerant, for example, while others need more water. Some varieties can withstand less sunlight than others. Rose varieties should also be pruned differently depending on the variety and your climate area.
The rose seeds can be planted right away if you have harvested them as late as November, December or January (in Southern California) or early spring after danger of frosts in your area. Place the rose seeds about one-half inch deep in a very light mixture of 50% sterile potting soil and 50% vermiculite. Some rose hybridizers use Sunshine Mix #4. You can use small pots or shallow trays to plant your seeds, whatever works for the space you have, as long as they have good drainage. Nursery flats work well for this. Lightly dust the rose seeds with RooTone or Captan before covering with soil. And then dust the top of the soil again, which will hopefully help to prevent damp-off (a disease which kills young rose seedlings). Amateur rose hybridizers concerned with toxic chemicals may want to periodically spray the seed tray with diluted peroxide and water instead of the more toxic Captan.
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.
Despite their reputation for being finicky, most roses are simple to grow and easy to propagate at home. “Propagate" simply means to reproduce a plant easily from a simple cutting. Unlike seeds, which produce very different plants, rooted cuttings produce replicas of their parent. You don't have to be a trained rosarian to reproduce treasured family heirlooms or favorite garden roses.
Site: For most abundant blooms and greatest vigor, roses need to receive 6 to 8 hours of direct sunlight each day. In hot climates, they will appreciate receiving protection from the most intense afternoon sun. In cool climates, a fence or a warm south- or west-facing wall can add enough extra warmth to boost flower production and reduce winter damage.
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.
Select the pollen parent flower. Remove the petals and harvest the stamens -- the male flower part that has the pollen -- as in the previous two steps. Check the stamens immediately to see if they are producing fluffy, mature, yellow pollen. If so, proceed to pollination. If not, look at stamens in the vials daily. Use them for pollination when mature pollen is coming loose from the stamens.