How many inches above the graft Union should you protect in case of a hard freez

[bovine421]

This little dip in temperature has got me proactive about protecting my trees. Instead of waiting to the day of the big event with my pants down pre-positioning mulch

[Galatians522]

As high as you can reasonably go. In the case of a catastrophic freeze you can potentially lose everything else. Many a young orange tree around here was saved by mounding sand around it until only the leaves stuck out of the top. That would have been about 12"- 14" above the bud union. I believe they don't recommend mulch for this as it doesn't hold heat as well. I also seem to recall that they sprayed the trunks with something to keep soil born disease down (copper?). They use tree wraps or teepees and microjet irrigation in the groves these days.

[bovine421]

Thanks for the information it's very useful. I'm very interested in the tree wrap that you speak of it sounds very user-friendly and practical. Hopefully reusable and as effective as advertised.
I went ahead and ordered some trunk  wrap from Amazon once again thank you and hopefully I'll have enough to do my piccabeen Palm

[Galatians522]

You are welcome. I am glad it helped. I am in and out of citrus groves a lot with my work. I often get the chance to observe and speak with the owners, and it is amazing what I can learn from them when I simply take the time to listen.