Does any one have experience with these? What is the coldest anyone has had any success with them?
They were developed for your area in your area. The bud hardiness ratings achieved through testing are:
Golden Lights -30F
Orchid Lights -35F (some say -45F)
Northern Hi-Lights -30F
Pink Lights -35F
Rosy Lights -35F
Spicy Lights -35F
White Lights -35F
Here is a link that might be useful: Azaleas and Rhododendrons for Minnesota
I have to say, I have many azalea in my yard, but this one just didn't make it. It was gorgeous when I planted it, came back one year and then just shriveled up and died. I have a true Orange one (sorry, I don't have the tag and don't remember the name) planted right next to it, and it's doing fine. I have them both mulched with pine straw for acidity, but I just don't know what happened to the northern lights
I have three not protected from winter in any way doing extrememly well.
I have grown Golden Lights, Orchid Lights, Northern Hi-Lights and all 3 have thrived with little care other than a light mulch. Our lowest temperatures are about -23. One thing in addition to looking at the flowers that I've enjoyed is that the Golden and Northern Hi-lights both have a nice scent.
I would think you'd do fine with some of the hardier of the Lights series.