Does anyone have any experience using this one as a parent? There is not much info available on HMF.
I had the option to buy it several times but it was probably the most drab color I had ever seen. Its a very odd shade of greyed-out pink. I figured there were rugosas equal with better color. For example, Jens Munk, is hgihly similar and is documented for a lot of positive traits. Pinkering lists Polar Sun as average in size. They list Polar Ice as slightly smaller. Polar Ice was slightly less drab in person but also easily passable without notice. They were both sold locally in the Portland metro a few years back and only sold when they went on clearance in autumn because they were the type of plants one could walk by without even realizing they exist. Polar Ice was definitely the nicer of the two as far as I could tell in person. It was more visible too. I am guessing the have similar parentage cause I am guessing the bland tones come from the old poly types. They looked healthy though, with nice branching habit.
I agree that Polar Ice is the more attactive of the two. No descendants listed on HMF so the fertility is questionable. I’m looking at fertile rugosa hybrids that are tetraploid or fertile triploids. Rugelda and Keith’s Delight are top of the list right now. Thanks Jadae.
I was kind of guessing both of them are diploids. The plants hint it, as well as the direction of the lineage. My second guess would be triploid, but I doubt it because rugosas tend to change dramatically at this point.
This is all North Creek Farms says about it:
"Admired by all who feast their eyes on this big beauty. A profusion of clusters of creamy-white double blossoms tinged and centered with shell pink. Sweet grass and strawberry scented new foliage.
6-7’ high by as much"
– no mention of hips but you can always call them. They seem friendly enough to give feedback. They also carry Rountuit, which may or may not be triploid. It could also be diploid like Topaz Jewel is. I do not see Yesterday’s Garden sold on any HMF links, and I have no clue about its ploidy.
Other options you may consider, other than the Kordesii recreations from Canada that have multiple layers of Rosa rugosa in them, is Hansaland (if you can find it), Hansa Park (looks like it is about 1/4 rugosa), Rheinaupark, and some of the newer Austin types. I cannot say whether or not they will match you needs or ploidy, but some of them are at minimum triploid and worth a look. William Booth is an example of one of the Canadian hybrids I was referring to. If you type in L83 into HMF, you can clearly see that it and a few of its descendants are heavily influenced by Rosa rugosa.
I wish I could help more.
Oh yeah, you can also see Paul’s work with L83. He has a whole litter of cuteness going on with it, so you can see its potential, as well as how it passes on the traits you may be looking for (or not) in tetraploid + rugosa.
Im blind, looks like you are already toying with it 
Does anyone know if Rugosa Magnifica is a triploid? Mine set hips yearly but that doesnt mean its not a fertile triploid. All I can recall about it was that it was compact, everyblooming, purple and good looking.