Just a guess, but it might actually be the heat, rose seedlings at least in my experience like it cool. Sometimes germinating in the fridge.

Also nicking or sanding a bit of outer shell of each seed helps speed up the process of breaking dormancy.

I don't know specifically about this particular rose but some roses are better than others when it comes to producing viable seeds

hope this is helpful

I moved them all to a covered screened gazeebo and watered em .... i had one tiny Brussel sprout sized thing .. could that be one .....

It could be. What you haven't been told is sometimes seeds can take a year or two, sometimes longer, to germinate. Much depends upon the condition of the seed when planted. Yes, you want the containers opened. Think about it. In Nature, the hips fall and rot, exposing the seeds which sit on the ground in the litter mulch. They frequently germinate all by themselves. Or, some critter eats the hip, digesting the pulp and fibers, passing the seeds encapsulated in "guano" where they fall to the ground and germinate. Sometimes, if the conditions have been appropriate and the plant in good shape, they sprout quickly. If the plant has been stressed enough, the seeds dried out long enough and conditions sufficiently unsuitable, they wait.

I was sent fresh seed from R. Xanthina two years ago. I planted half last year with no seedlings resulting. I'd transplanted the seedlings surrounding them in the seed table and knew which were neighbors to the Xanthina seed. Suddenly, there were Xanthina seeds germinating in the other seedlings, the second year after planting. This year, I planted the second half of the Xanthina seeds in the tables. There are two seedlings from those seeds right now in the tables.

Banksiae seeds are known to usually require two years to germinate. Several years ago, I had one germinate from freshly collected seed after only four months under soil. None of the others germinated before I reused the soil. This year, I planted a large amount of fresh Banksiae seed I collected in the garden. There are three seedlings right now from seed which has been planted only three, nearly four months.

Bottom line is, you can set the stage for optimum germination in attempts to stack the deck to get what you want, but they are going to do whatever they decide to do based on a variety of factors. Fortunately, many do as we expect them to. Good luck! Kim