posted 5 years ago
I'm in Zone 7, with hot (to Seattle-raised-wimpy me) humid summers regularly in the 90s. The weather charts don't back me up, but trust me the last few summers have been unpleasant. Meanwhile, it's currently snowing. Sigh.
I inherited several currants and 1 Jostaberry in full sun and they are doing fine. The Jostaberry is about 5 feet tall and badly feeling its age, but it's usually covered in berries. (I let the birds have them as I like the currants better and tend to be overwhelmed at harvest.) I've also planted several currants in part shade and they're small but started berrying in the second year, healthy amounts (for scrawny shrubs) the next year. I also inherited 1 black currant in partial shade and it seems to be not as big and not as fruitful as the one in full sun.
So my personal inference is that currants/gooseberries/Jostaberries would prefer full sun, but will bear fine in shade, and let's face it most of us have about fifty other things competing for sunny spots, so might as well plant the currants in shade.
But if you've already planted it, it should be fine in full sun. If all else falls, let some suckers air layer and plant them in a shady spot to compare.