I do add sugar to rhubarb; but a whole lot less than recipes generally call for. I add it bit by bit, and taste, and stop adding while the result is still quite tart.
If anyone cares, my blueberry pie recipe uses zero sugar.
I’ve been experimenting with the whole concept of pie-baking, starting with the no-sugar part. It was suggested that I could make a crustless sort of pie by using berries, butter, and some commercial pie mix like Betty Crocker, but that came out too moist no matter how long I left it in the oven, so lately I’ve been buttering a Pyrex pan and dumping layers of Betty Crocker (actually Aldi’s rip off with the same initials “Better Cooking” or “Best Cuisine” or some BC lookalike), mixed with an egg, and then a layer of unsweetened fruit, another layer of BC+ egg, with some dry cereal, and it’s been tasty/ But no sugar at all–I like my pie tart anyway.
On the rhubarb count: six. My two youngest and I like fresh rhubarb without sugar.
I adore rhubarb.