It seems rhubarb once established thrives on neglect. I have the the same experience with KangaRu. Three years in the same spot, not much to show for it. Northern Illinois
I would recommend going with seeds from French Harvest from Australia. You can search for information about it on this forum. Mine has done exceptionally well compared to my other seed grown strains (probably tried 5-6 over the years) pplor roots I got from Nourse Berry. In fact I typically kill my seed grown varieties except for Victoria (vigorous but bolts every year and the stems are coarse, and too spongy to use by end of July.) The Nourse variety grows every year but gives me 6-10 inch stems whereas French Harvest seedlings were producing 12-18 inch stems, and the Nourse plants often disappears by end of July
My second years were producing long thick dark red stems that produced into fall here in Southern PA (7A). You could grow out a packet and keep the best ones in year 2.
i grow Canada red or crimson red. don’t remember exactly but its 3xs more productive than a heritage rhubarb i grow that my family has brought over from Quebec back in the early 1900’s. it sweeter and a lot more tender as well. i plan to cut some root from my 4 patches to grow more of it and sell it at the farmer’s market. a guy last spring showed up there with a marine cooler full of rhubarb last summer and was sold out in a few hours. in your zone id think it would be equally productive for you. i only give it a top dress of manure every few years and it puts out 3ft stalks and lots of them. rhubarb loves my clay soil as long as it’s on a slight mound.
What seed rhubarb varieties do you plant? I’m in 6b and have had good enough results from Tractor Supply Co Victoria rhubarb that I’m curious to try others.
Which variety of seeds did you get from French harvest?