Chestnuts: delayed graft failure

I've finished Akiva Silver's excellent book, "Trees of Power", and I'm jazzed about trees all over again just in time for late fall/winter planting...my favorite time of year.

But he says something worrying about chestnuts as my final 2019 tree order shakes out, containing as it does mostly grafted trees:

"[Grafted chestnuts] can have some serious disadvantages. The most important one is that they suffer from delayed graft failure. This occurs in about 50 percent of grafted trees. The top of the graft will die three to five years after it's been made because of incompatibility issues. Some growers state that this won't happen if the rootstocks are seedlings of the cultivar you are grafting. I don't think that's true, though."

Gah!

Why, then, are most chestnut trees grafted? Respectable growers like Burnt Ridge, One Green World, Raintree etc offer mostly grafted trees, so it can't be as bad as all that! It is worth noting that Burnt Ridge, known for its chestnut research, is the only one offering layered trees. Threads on permies make it sound like air layering isn't that hard, so why is the method so rarely used in propagating chestnuts?

I wanted half my trees to be layered, but those sold out before I ordered in early Oct. Now I'm falling back on large seedlings and adding even more grafts :(.

Anyone got another Western source for layered chestnuts?

What's your experience with any of the above?

i can't speak to out west, but the pro chestnut growers i know in OH/MI are only using seedlings in their orchards, no grafting, no layering, no named cultivars. they're selecting for size, flavor, and blight resistance, and all of them say that their seedlings are stronger, healthier trees with better tasting nuts than the cultivars they used to deal with. i think that might be partly because they're getting more experience with trees with asian genetics, and many of the big euro cultivars are fairly bland comparatively.

An interesting discovery has been made about grafting nut trees. It's been found that if you use a seedling from the tree whose scion you're using, the rejection rate is far lower. I know at least one nursery which practices this


But, seedlings are fine in my opinion. They just take longer to produce and are variable

James, Akiva Silver says he doesn't believe that bit about grafting scions to the same variety rootstock, but I'll try it. I'm trying everything because I want to get at least some of it right the first time...I don't have time to try again in five years. Hit the planting once with a significant sample of each tree type. I suppose the interest in grafts is because people are impatient, and that's why all the growers who Google at the top of chestnut trees are grafters.

Greg, no named cultivars? That's all I'm finding! Are you saying they're raising anonymous asian-hybridized trees from seedlings? I'd be excited to try that, but I'm limited to what we have in the Pacific Northwest. We have a blight embargo on chestnuts from outside our region. I'm not even sure I can order them from California.

chestnuts I'm growing are all from seedlings, Chinese and dustan, would love to get some of the new American resistant seeds

You might try burying the graft if it's a concern. And like I mentioned, seedlings are perfectly acceptable too, like Bruce is using

Fredy Perlman wrote:Are you saying they're raising anonymous asian-hybridized trees from seedlings?

one guy says he has genetics from all 7 (?) world species in his stock. but yes, multi-species hybrids with blight resistance from the asian ones. we get seed from him for planting projects almost every year, but i have no idea where to get blight-free stock that's similar.

This is an interesting thread for me, as I've been grafting lots of chestnuts and I'm curious to see how they play out.

So far, what I've noticed is that at least half of my grafts fail from the get-go. No callus formation, no shooting from the scion. Dead as as a doornail.

Of the ones that take, I'm seeing good results. I tend to do a dual leader, with one side the seedling and the other side grafted. This is not just to hedge my bet, but also for better pollination. One of the things I want to do with all these grafted trees is plant them around the village, and if one is by itself then it should have a pollinator side.

The oldest of my grafted trees is in its fourth year, second in the ground. The scion side leafs out weeks ahead of the rootstock and this spring it's already got flower catkins in early November, which is pretty remarkable because our chestnuts normally flower in mid December. Some of the newer grafted trees, still in bags, are showing similar traits. with scions showing more spunk than the rootstock. I wonder if this may be a sign of future incompatibility...hard to put it together, because the rootstocks are obviously supplying the scions with everything they seem to need.

NB: These are European/Asian varieties and hybrids. I'm not completely certain of their provenance and there might be some American genes in there somewhere, but they are mostly the generic chestnut trees that we get in NZ. I'm hoping to get a few strains that are more tolerant of summer drought, as that is a deal killer for the older trees on the property.

Phil Stevens wrote: I'm hoping to get a few strains that are more tolerant of summer drought, as that is a deal killer for the older trees on the property.

Does anyone know which strains are most drought tolerant? We get pretty bad summer drought but I've never heard cultivars differentiated based on this

I ordered a set of grafted chestnuts also from burnt ridge that arrived in jan 2019. That would put them at year 3 now. I hope Akiva is wrong and they don't die in another year or two. That would be really sad. I do however have some seedlings that I started from both parents so I could replace them if I needed.