I uprooted my kumquat tree, roots and all, but sometime later, a sapling came up in its place. It’s been about3-4 yrs growing and has blossoms. It’s fruit looks like a Eureka lemon but dark green. Could the stress have mutated the original kumquat?
Kumquat is usually grafted to the root stock of another citrus variety since it takes so long to grow from seed. Often it is citrus macrophylla. Probably a bit was left after you dug it up and that is what is now growing.