Rose hips are the natural seed container for the rose plant. If the flower is allowed to mature on the stem, the base of the flower forms the hip. Wild roses naturally pollinate themselves by the action of bees and other insects. This makes the process for wild roses easier than growing domestic roses from seeds that sometimes result from selective pollination by human action. The process takes time but most gardeners with basic tools and skills can nonetheless do it successfully.
Select the wild rose plants you intend to gather seed from. It might be tempting to pick the prettiest flowers for display but allowing them to mature instead will furnish seeds for the next generation of wild roses. If you are selecting roses from a wild area, note the location of the plants when they bloom. Return in the fall to gather the hips.
Clip the hip from the stem. Depending on the plant and environmental conditions, some hips turn red or orange when mature while others remain green. Remove the rose hip as soon as the hip begins to wrinkle.
Slit the hip open with a knife. The hip contains seeds as well as some membranes that may have dried out into a dust. Separate the seeds from the other material of the hip.
Place the wild rose seeds in a baggie along with some potting soil. Place this mixture in the refrigerator for about three months. This process is called stratification and mimics the natural process of the seeds laying dormant through the winter before germinating the next spring.
Remove the seeds and place in potting soil that is held by small pots or seed flats. Plant one or two seeds per pot about ½ inch deep. Rose seeds germinate in about 1 week and viable plants should form within 6 weeks. Transplant the wild roses into the garden after the last possible frost or transplant into larger pots for container gardening.