Wow, thank you so much for the reply! But just to confirm one would be allowed to buy online a grapefruit, lemon, lime, or any other hybrid fruit tree and plant it?

ב"ה Shalom Allow me to do some finetuning. In wake of your current question, I did a little editing to my previous answer. To make sure I am correctly understood. There are two things. Hybridizing and crossbreeding which are the mixture of two different species, which is forbidden according to the Torah . Grafting is the act of connecting two different trees so that with the benefit of the stronger tree, the tree grafted will produce more fruit. When the grafting is done between two different species, this also forbidden according to the Torah. When the grafting is done between trees of the same species, it is permitted. In regarding to citrus trees, there is disagreement among the Rabbis if all different types of citrus trees are considered one species. According to the Chazon Ish, since we are in doubt if citrus trees are not necessarily different species,in regard to the grafting of an orange tree with a grapefruit tree, for example, Rabbis are more lenient in regard to the grafting of citrus trees. In addition, there is leniency of the Chatam Sofer, that if the non-Jew already grafted the two trees , once the grafting is completed and is no longer noticeable, on may maintain the graft. So again, I repeat, if there is grafting of two trees of the same species, (which is grafting, not hybridizing two different species), which you are buying on line, you may plant them. This is the guideline which must be applied . I cannot answer, especially not on the internet for every individual case. I hope I made things a bit clearer. All the best