I can't bury anything that big (physically), and looked up those factoids about Bristol. It propagates from I guess it would be nodes on the root and if you want more, you have to bury the tip several centimeters.
I don't really have an ideal place for them here, and they need lots of water and fertilizer in the spring and other things for optimum cultivation. I'll be lucky if I get these in the ground soon enough to set roots down further to survive the winter. I'll plant mixing compost with the soil and lay out cardboard or layers of newspaper covered with lots of grass clippings which is all I have for mulch. In the fall I hope I can grab some oak leaves from the neighbors, lost my mulch maple tree last year. Oak leaves are the best.
I think both red and black like slightly acidic soil but need nitrogen fertilizeer so have to watch the ph and I don't have a tester. From your high yields, you're doing it all right. I will have to remember the fruit on the cane the second year and then the cane is done, hope I can tell the difference, should be similar to roses.
I have some red ones in the fridge from the store, frozen, thawed and have to add your own sugar now, got them for a treat. I like them over vanilla ice cream.
Thanks so much for the response. I wish I had some veggies going as that's what most here are doing which is a good thing.
I forgot to mention that our planting is over 20 years old. Our soil is on the acid side of the PH scale here in the Redwoods and I do fertilize a couple of times a year and water regularly. In another climate the Heritage would put on 2 crops I believe?