Buluku is a white mulberry. I haven't had fruit from it yet. It's grafted onto rubrus (red)/native mulberry - which I've been able to root a number of and it's doing well as a very vigorous rootstock. I should trade some scions this year (pear/mulberry/persimmon) but just so busy.
We had a Romance sour cherry (Carmine Jewel) that put on over 30 lbs for us a few years back - and they were excellent. That's the one I was taking rootshoots from. I did not fruit like that consistently though, maybe late frosts, but perhaps more likely we don't get quite enough chill hours?
If I were in 7a, I would plant one of those series
"These cultivars from the University of Saskatchewan's Romance Series are self-rooting, meaning they are propagated vegetatively (e.g., from cuttings or tissue culture) and do not require grafting onto a separate rootstock. This is a key distinction from sweet cherries, which are usually grafted."
1. Carmine Jewel: Most productive, with 25–30 lbs per plant, early ripening, and excellent for processing. Known for consistent performance and high yields, even in harsh conditions.
2. Valentine: The most productive for some growers, with bright red fruit and large shrub size (up to 9 ft). Ideal for drying and processing due to its color retention and high yield.
3. Juliet: Best for fresh eating, with sweet flavor (up to 24° Brix), early ripening, and good cold hardiness. Highly palatable and avoids major pests due to early harvest window.
With some sources mentioning suckering as a problem with Juliet - sounds like a FEATURE, not a bug to me.