Grafting different varieties of avocado? Utuado and Haas

[apullin]

Hi folks,

Can I craft Utuado scions onto Haas rootstock?

I have a nice Utuado tree that I got 3-4 years ago, and it's grown a lot. But it does have some thin lower branches that almost certainly will need to be pruned away.

But I also sprouted tons of seeds from Haas (grocery store avos), and also lots from a random non-commercial variety (Stewart, maybe) growing in my neighborhood.
I did it for fun, but it got out of hand, and I definitely have 20+ trees ranging in size from 2ft-7ft.

As those from seed will almost certainly be useless, I am considering trying to graft them to something known-good.
I suppose I could also take Haas scions from a commercially grafted Haas (or other) tree.

From some searching, people seem to say that all avocados are one species - does that imply they might all be graft-compatible?

[spaugh]

Thry are graft compatible and you can graft whatever you want on them. 

[apullin]

Oh. That's good news.

Follow-up question for anyone: I let some of the sprouted seed avos grow probably too tall/thick. If it's ~15mm wide (4+ feet tall), is that too tall to graft onto? If not, is there a specific height I should cut it back to, and a grafting technique to use in such a case?

(I actually have never grafted before .... if there's anyone in the SF bay area who either wants to show me or wants some cold hardy avo rootstock, let me know ... )

[drymifolia]

As those from seed will almost certainly be useless, I am considering trying to graft them to something known-good.

They will not be useless. They will take a few more years to start producing, and the fruit will not be an exact match to the parent cultivars, but most seed-grown avocados that I've tried were of similar quality to the parent tree. It's a gamble to be sure, but most will be ok quality probably. Some may be great, some may be bad.

Cleft grafts work well and are fairly easy to succeed with avocados if you have scions about the same diameter as the rootstock (or you can do two scions per cleft if the rootstock is about 2x thick). Here's a basic cleft graft diagram from The Grafter's Handbook:


I've also had good luck with bark grafts a couple times where the rootstock trunk is more than 2x thicker than the scions.

You will want to get good parafilm or buddy tape and fully wrap the scion and graft union to prevent desiccation while it calluses.

[apullin]

They will not be useless. They will take a few more years to start producing, and the fruit will not be an exact match to the parent cultivars, but most seed-grown avocados that I've tried were of similar quality to the parent tree. It's a gamble to be sure, but most will be ok quality probably. Some may be great, some may be bad.

Oh. How interesting ... I thought the convention wisdom was that avocados were a total dice roll on quality, even if the other characteristics (skin, size, etc) were similar.

"1 in 10,000" I think I remember hearing.

[drymifolia]

Sounds like something a nurseryman trying to sell grafted trees would say.

I may also have a wider range of what I consider an acceptable avocado than some people. I like most Mexican-race and Guatemalan-race avos as long as they don't have fiber issues in the flesh or ripen too unevenly, which are the main things that could produce loser seedlings. Some are a bit bland, some are more nutty tasting, some have slightly vegetal or earthy flavors, but as long as it's eaten when properly ripe, I've never had any with flavors I found particularly offensive. Oil content should be satisfactory in seedlings of Hass or Stewart. West Indies race avocados (i.e., FL/Caribbean types) can sometimes have more unpleasant/funky tastes, or overly watery flesh, but that's not relevant for you.

The number of years to maturity is the huge unknown. Your 7' trees might be a couple years from flowering, or on the other extreme they could be 20 years from flowering. Grafted trees should start producing within a couple years or so.