You're welcome! At higher latitudes, they are going to require longer periods of "blazing sun". The closer to the equator you get, the more direct the sun's rays are, hence the stronger the radiation and heat. It's "brighter" the closer to the equator you travel. That's something you really had to pay attention to in photography back in the old film days. Where you may have needed higher ASA (American Standards Association) ratings (perhaps ASA 200 or even 400) to photograph a trip to Northern Europe or Canada, if you used those more light sensitive types for a trip to Hawaii, you would likely over expose most of your photos as the light would be too strong, too bright for the film speed. For those, you probably would have wanted ASA 64 or even ASA 25 slide film. Length of direct sun duration for plants is pretty much the same thing. Your foliage in six hours of direct summer sun there in NJ is probably going to look great. Six hours of direct summer sun in inland valley areas of California, AZ, Texas, etc. will likely fry the foliage and eventually kill the plant by cooking it. It's all a matter of intensity, something the old rose writers never considered as they wrote for the other rose growers there in Britain, so they all had the same light.