(Montana) I have successfully overwintered Sunpatiens in my home/hobby greenhouse in Zone 4. But there is a catch that I discovered only after failing for several years in a row. It's labor intensive to keep them monitored and requires chemical warfare to keep them alive and growing. If you're not willing to use fungicide and miticide, don't even try it. (Cuttings in water might still work) First of all, Sunpatiens seem to be quite prone to stem rots, but that is easily fixed with fungicide and a fan. Here's the biggie with these gorgeous plants though: mites! Not the regular two-spotted spider mite that affects almost every other plant and are fairly easy to control. New Guineas catch the Broadmites, which are way teenier than regular mites. (You are hard pressed to see them even with a jewelers eye-glass) And they require a special pesticide. (I use Akari). As if that isn't a big enough pain in tuchus, NGs are also prone to aphids and thrips so applications of regular insecticide is usually required too. Good Luck!