I would cut the thorny suckers and throw them away. They are most likely from the rootstock and therefore are not an edible fruit. Next I would cut the satsuma about halfway back and throw all the cuttings away. And third I would stop neglecting it. After all that my guess is that the tree will start growing well and eventually produce great fruit.

Thanks for the response.
I was away all summer, so I did not neglect it on purpose.
Also, I meant that I wanted to root a cutting from the sucker of the rootstock, and take a healthy cutting from the top, and splice it onto the new rootstock to make another tree.
That was my question.
Dave

Hi Dave
I am sorry I didn't intend that to sound like I was blaming you. I realize that things just happen. What I was trying to get across was the fact that citrus can take abuse like that and if you start taking good care of them again the chances are that they will come back strong. But cutting it back is an important step in that process. I would not attempt to root a cutting from the rootstock and then try to bud that. Budding can be tricky as it is on a healthy rootstock grown from seed.

There's no reason why you can't do as you suggest, but it may not be so easy. Some rootstocks are very difficult to root as cuttings. Poncirus trifoliata cuttings have never worked for me. Citranges may be a bit easier. Ideally they would need bottom heat and misting to root. Growing these varieties from seed is a more reliable method and generally eliminates the risk of diseases.
Then you would need to graft or bud the top variety. Sounds like you may not have done this before. Not too difficult, but needs practise for reliable results.
Give it a try!

One of my citrus died last winter, but of course, rootstock continued growing..I left it intentionally, cut the top, and planted in the garden this spring..
But, the rootstock is rooted, so this has nothing to do with the original thread, just thought I'd mention in passing..It's an experiment. Wish I knew which stock it was though..Poncirus is the most hardy..Living in Il, it be nice growing any citrus fruit, even though basically inedible..lol..little oranges. I'm going mulch around its base..there's no near outlet to plug Christmas lights so that's out..if it lives, great, if not, too bad.
Dave, go to either Briteleaf or Harris Citrus..Email Anna from Briteleaf or Ruth from Harris and ask if they have any suggestions on rooting/grafting. It can't hurt, and would be a great experiement..Toni

Toni if your rootstock's leaves drop like a deciduous tree would then it may be Poncirus. If it doesn't then it is not. Also can you post a picture of it growing especially the leaves and someone here may be able to ID it for you.

Citrus, thanks..so, if the rootstock isn't decidous, that means it's another type of stock? If that's the case, more than likely, it'll die in winter since Poncirus is the hardiest.
A few years ago a smaller Poncirus was planted out front. During winter, (on one of the darkest nights) someone trampled the poor plant and it died, but it lived 3 or 4 yrs, outdoors, protected with mulch, no lighting.
I'll snap a pic in a bit. Thanks so much..Toni