Experimenting with a few things… Why not leave the hips on the bush over winter? It would seem if that is the normal process of nature that it may do something to the seeds to prepare them for germination… Have no clue really, just thinking out loud… Has anyone had any success or more success this way?
I live in zone 5 northern Ohio. I often go to public parks and pick rose hips in the spring; but they are mainly winter hardy roses like rugosas. I have no experience with picking hybrid tea hips in the spring. The following link gives one person’s experience.
The general rule of thumb in areas with freezing winters seems to be that spring picked seeds will have some germination but not as high a percentage as fall picked seeds.
Thank you for your information, very helpful!