Nearly all species germinate best with a period of cold stratification, while others benefit from a warm stratification period followed by cold stratification. Below is a general outline of some methods for germinating rose seeds. Keep in mind that each batch of seeds will vary in germinability based on growing conditions during seed maturation, seed ripeness, seed storage time and presence of disease or insect pests. Harvest rose hips that have just begun to turn red or orange and before the pulp becomes soft. Seeds from just a few hips can be extracted by hand by cutting into each hip and digging out the seeds.
Larger quantities require maceration and floatation.
Soften the hips in a container of water for 1-2 days at room temperature. Macerate the hips by rubbing them against a metal screen or soil sieve or mixing in a blender with water. Wash the pulp thoroughly, and most seeds will float to the top where they can be separated from the heavier hips. The cleaner the seeds, the less contamination you will get during germination. Dry the seeds on absorbent paper for 1-2 days.