Halachic preferences for rootstock, specifically for Kumquat scions and similar types like Calamondin/Phillipino Lime
Question
I hope you're doing well. I have a question regarding the halachic preferences for rootstock, specifically for Kumquat scions and similar types like Calamondin/Phillipino Lime (which is a mandarin-kumquat cross). Based on the image on your website, I'm trying to understand where Trifoliate rootstock fits into the halachic preference table.
I noticed that Troyer is listed as a permissible rootstock preference 2, and since Troyer is a citrange cross between trifoliate and navel orange, I'm wondering if there might also be a reason to permit pure Trifoliate (Poncirus trifoliata) rootstock with a Kumquat and/or Calamondin scion to be planted by a Jew in chutz la’aretz lechatchilah?
As always, I appreciate your clarification and assistance on this matter.
Answer
It is permissible to keep taking care of all of them after-the-fact (to say whether it is lechatchilah to graft or plant any of them, he would have to see the scion and rootstock themselves).
In general (and going forward), there is a machloket whether all citruses are considered one species or not, so a non-Jew should plant grafted citruses unless the scion-rootstock pair are within the same halachic family. But since it's a safek, you would be able to continue to keep and care for the trees.