graftingg additional roots on trees

[Walt]

There is already a couple of threads on grafting additional rootstocks on a tree to help it grow faster and/or better.  One is "Multiple rootstock grafting" on a non-citrus.  I think there was one on citrus but I couldn't find it.  So I'm starting a new thread because I need advice.
A year ago I bought an Etrog from Logees and got a nice healthy tree but in a tiny pot.  I potted it up but it quickly declined and died.  I think it didn't have enough roots to absorb enough water in the hot dry windy climate here in central Kansas.
So I decided to buy another and graft on 2 more rootstocks.
The Etrog is about 35 cm tall and in a pot about 5 cm square and 5 cm deep.  The rootstocks I have are Citrus x Ponciris but I don't know which variety.  They are a little smaller than the Etrog.
My plan is to plant all 3 in a 3 gallon pot and use approach grafts to join them and cut off the tops of the 2 new rootstocks after the grafts have taken. 
One problem I see is keeping the Etrog alive until until the grafts take.  Another problem is that it is up to 100 F just now and this is a bad time to do all this.
Any advice is welcome.

[vnomonee]

I tried approach grafting sour orange to my citrus medica turunji, which stubbornly keeps rotting. Also from Logees. It didn't work. The sour orange callused but the turunji did not and died of root rot before it could take. I have one more cutting on own roots which I just cut at the top and grafted it along with a small leaf to sour orange and placing it in the shade.

I would do some backup grafting if you can incase your approach doesn't take.

I've had success doing this type of graft with a leaf still attached and putting a bottle over it in the shade so I figured I'd try it with the turunji since I don't have large enough scion nor buds to do bud grafting.



Turunji with top clipped off

[Walt]

Then I maybe should do a cleft graft onto the two rootstocks I was going to  graft onto the Etrg.  And that would reduce the size of the Etrog tree a little making it less of a load on the small roots.

[1rainman]

For growing in pots it's better to do rooted cuttings. They have a shallow root system and grow small and bushy but will get big fast enough. Even with cuttings many varieties seem too big for pots. Flying dragon is dwarf but grows slowly. Everything else is too big for pots when grown from seed.

[Walt]

There are enough branches I can try several ways.  So I'll try rooting cuttings too.

[drymifolia]

Is etrog compatible with trifoliate? I know some lemons and citrons have weird graft incompatibilities. Maybe try some lemon seedlings as rootstocks too?

I wonder if part of the problem you're seeing is a delayed incompatibility with whatever rootstock the nursery used.

[caladri]

Is etrog compatible with trifoliate? I know some lemons and citrons have weird graft incompatibilities. Maybe try some lemon seedlings as rootstocks too?

I wonder if part of the problem you're seeing is a delayed incompatibility with whatever rootstock the nursery used.

This article (https://www.actahort.org/books/1130/1130_65.htm) seems to suggest that citrons produce smaller trees with smaller yields on trifoliate and trifoliate hybrids, performing much better on sour orange and Volk. The best performance on a trifoliate hybrid seems to be on Troyer citrange. That article also provides some interesting background and context, including noting that no outright incompatibility was observed, so for dense plantings (and maybe also container plants?), trifoliates might make good rootstocks.

[vnomonee]

I made a video to show how I rescued my citrus medica turunji.
10 days after grafting with my baggie/bottle method the turunji is pushing. It seems really fast for a graft.

https://youtu.be/NlxhkhSfBb0

10 days later

https://youtube.com/shorts/wDYDq7Ve1Vc?feature=share

Changed over to a bottle because the wind kept using the bag as a sail ⛵