New kumquat tree
We purchased a new kumquat tree from an online nursery (I forget the name) and it arrived with good instructions for starting it in a healthy manner. We planted it in a container (may get replanted in soil or a larger container later...we have a successful kumquat "tree" about 5 feet high in a large container now). The new one looks healthy with new growth in the plant now. It is about 20 inches tall. My question: There is a separate branch that has started to grow out below the foliage and it does NOT look like kumquat. It seems to be growing from the original trunk that looks different from the kumquat trunk. Original trunk is in the soil and is gray/brown stripes and about 3/4" diameter. Kumquat trunk, same size diameter but solid green trunk. Just below the graft that joins the two trunks, there is a branch shooting out, about a foot long, that has a series of three green leaves in groups along the stem of the branch. Additionally, the branch has sharp spikes, abut 1 1/2 inches long spaced along the branch. Definitely NOT a kumquat branch. Can you ID the branch and what to do about it. I think it logical to cut it at the base but I don't want to harm a healthy kumquat-to-be. (It's more like a shrub now).
Your Komquat tree is a grafted tree. The root stock is of another citrus cultivator.
You need to cut these sprouts off of the tree, as soon as they appear. They take energy from the tree and can take over from the tree.
Prune them with a sharp garden shear.
Only the grower would know the name of the room stock that they used, there is no way to identify it.
Citrus do have thorns and the root stock is a citrus, of some type.
Here are some links with more information.