Is it possible for my kumquat tree, which hasn't produced fruit in many years, to suddenly be growing a different type of fruit? We were decorating it for Christmas (it's about 25 feet tall now) and noticed very dark blue to black berries on it, about the size of peas. How is this possible? Crazy, huh? Have you ever heard of this happening? Thanks for your help! Robin Rowan
Certified GKH Gardening Expert
Kumquats are grown unto root stock of another citrus fruit.
It is possible that the fruit you are seeing is from the root stock.
I was unable to locate any image that would match the description that you have given.
Here is a link that describes the most common root stock used.