Basic Tips for grafters #4 Why grafts fail

[CA_Poppy]

That is a super cute dog!

[Ginda]

@hambone

How much longer? What kind of graft?

They are maybe 6-8 inches. I didn’t actually count the buds. (Which are now under Parafilm.)

Cleft graft? I cut the bottom of the scion into a “V”, split the stock, shoved the “V” until the stock, tied it up with rubber bands, and covered the whole shebang with Parafilm.

[hambone]

Here’s a conversation thread on Long Scions where you’ll see names of people who use a lot of long scions:

Scion Length

Am intrigued to notice lately more and more very long scions some people are grafting, some look the better part of a foot. Is this something new? I recall reading, hearing years ago when I learned that you normally left two, maybe three buds on the scion. Is there any downside to the longer scion, other than needing more wood? If the longer scion accelerates fruiting I’ll start doing it immediately. Learning new things all the time!

[Ginda]

Thanks, that was exactly what I was looking for.

I think the damage I did to the trunk now bothers me more than the length of the scion, but I expect it will heal if I can keep the critters off of it. And I got a really good join between the stock and the scion.

[YumYumTrees]

Regarding temperature to callous the graft of plums, will a new bench graft callous if its placed outside and the temperature is above 60 during part of the day, but in the 40’s - 50’s ( and possibly thirties ) at night? ( grafts are in pots )

[Ginda]

Well, they took a while to sprout, but all my grafts this year seem to have taken. I nipped off the sprouting buds on the stock today, in the hopes of sending more nutrition towards the scions.

[svpal]

Can a graft fail if the tape/string is too tight? This would be for a thin scion and stock (3mm dia) grafted using carefully done Whip and Tongue. Rootstock is a OHXF-87 pear rootstock and scion in Warren pear.

[Gkight]

I would say it can only help the graft take, but if it’s too tight (and doesn’t decay naturally like buddy tape) you may want to remove it manually after the graft callouses.

One more cause for graft failure that I saw Mark mention is birds. I have annoying mockingbirds who love to land on new grafts, so I tend to wrap them in aluminum foil to protect the graft from drying and those pesky savages for landing on them leading to lost cambium contact and failure.

[marknmt]

I think that one year I got so carried away wrapping grafting rubbers on cleft grafts that I choked a few, meaning I squeezed the cambium to the point that it couldn’t transport nutrients. So I think that maybe it is possible. Or maybe they struggled for other reasons. I don’t remember all the details.

In any event the wrap does need to be nice and snug.

[ramv]

In my experience grafting rubbers simply fall off after a season. And have a decent amount of give. So they have never choked a graft. The ones from amleo and others are intentionally made to be more stretchy- less taut than a cut rubber band. That is what I would use.

However, I’ve almost killed many grafts with buddy tape and/or electrical tape. Often discovered them just in time - it’s an ordeal to cut them off without damaging the underlying plant material.

[DennisD]

I quit using grafting rubbers about 5 years ago because I began to find that 1” wide strips of plastic gave a more uniform pressure to the grafting union and it can be applied with plenty of tension to encourage callousing. In cases where larger diameter stiffer scions require more pressure to close the gap, I apply electrical tape over the plastic strips sealing the graft union. Then as soon as the graft takes I remove the electrical tape to avoid girdling the graft union. I apply parafilm to the scion before grafting to protect from dessication, so the complete graft is sealed when done. My Plastic strips are cut from plastic bags using a safety razor: cheap, reliable, easy!
Dennis
Kent, Wa

[sammity]

What about rootstock-to-cultivar compatibility in apples? I haven’t seen much about that with apples, so have presumed it’s not an issue. I’ve had trouble with a getting a few particular cultivars to take, though, so wondering if it’s compatibility, or just coincidence.

Specifically, the two I really want to work with but have had trouble with are Lodi and Haralson (I’m sure there are others, but haven’t noticed patterns). The Lodi is from our mature tree (I’ve had good success with other neighborhood trees I’ve taken scion from), and the Haralson from a few sources - I think Fedco, 39th Parallel, maybe Cummins. Rootstock last year was G.214, G.212, and some B.9 and M.111. What have you all grafted these on? Other thoughts on compatibility?

Thanks, all!

[evilpaul]

Some of the Geneva rootstocks are highly susceptible to latent viruses. I’m not sure if you would get an immediate graft failure or just the death of the whole tree after some period of time?

There’s some known incompatibilities. “M.26 has graft union incompatibility with some cultivars like ‘Rome’, ‘Stayman’, ‘Golden Delicious’, etc.” I think Haralson has come up as one that’s given other people here problems?

[marknmt]

@evilpaul

I think Haralson has come up as one that’s given other people here problems?

I had trouble grafting Haralson, and after it took it was slow to take off and slow to bear, didn’t want to grow out, curling up instead, and is still not very vigorous years later. A fine apple, though.