Found some hips with one or two good size seeds in it. After drying the hips (I forgot them in my jacket-pocket) soaking the seeds for two days, I put them bagged in moist coarse sand in the fridge at 1°C for two months to come.
Of all the seeds that germinated, just one seedling grows well. The others got badly affected by mildew. Some already died, but I will still give the others a chance to recover.
