Q. This year I noticed branches growing from the base of my orange tree and the branches have sharp thorns on them. Should they be pruned from the tree?
A. The branches growing from the base of your tree probably are shoots arising from the rootstock; common name, “suckers”. Let’s use your orange tree as an example but it could be other citrus as well such as limes, grapefruit, lemon, etc.
Most citrus valued for their fruit are grafted to another citrus valued for its roots. This citrus valued for its roots is called the rootstock. The citrus plants used for rootstocks are selected for various characteristics but not for the quality of the fruit they produce. In fact fruit from rootstocks is nearly always pretty terrible.
The rootstock may sometimes be more vigorous than the orange tree itself. The rootstock can send up shoots that, if not removed, may dwarf and overtake the orange part of the tree. Simply remove these undesirable suckers any time they appear and as close to the trunk as possible.
They may sucker from the roots as well. Remove these too by cutting the sucker and the root with a sharp shovel and pull them from the soil. This eliminates the possibility that the rootstock will overtake the orange tree. Do not leave any stubs. These will easily regrow.
Frequently in our climate tender citrus like some oranges, limes and others are killed during winter freezes. But because the rootstock part of the tree may be more cold tolerant it survives, then suckers and takes over.
In a couple of years the rootstock is the only plant left and the owner wonders why the fruit is terrible and not anything like the citrus fruit he was expecting.