The amazing Duke Avocado

@swincher Thanks for reminding me. An update is certainly overdue.
The tree is mature enough to flower (born February 2019), and it does so very profusely. The tree is absolutely covered in flowers. Last year was the first time it did so, but a late frost killed them all. However, the tree itself didn’t seem effected at all except for maybe a few leaves with brown “burn” marks.

This year we had no such misfortune, but despite plenty of pollinators and tons of flowers and no frost, no fruit set at all. I’m far from an avocado expert, but it sure seems like the tree needs another tree to cross pollinate with. I don’t know what else it could be, unless this is the nature of growing it from seed and some genetics misfired or a female/male kind of thing. So if someone could share possible reasons, I’d appreciate it.

With no further ado, here’s a picture of how it looks today. I’d estimate it being around 13-14 feet tall. I feel like I need to prune a little to balance the tree out. Not sure why it started to grow the way it did as it was very uniform the first couple of years. I have not fed it in a long while, so I’ll do that later today.

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Even in a large, mature tree with a nearby compatible pollenizer, only a few hundred fruit usually are held to maturity despite well over a million individual flowers. Something like 1 out of 10,000 flowers. Smaller trees do sometimes have higher fruit set, but not hugely so.

For your tree it was probably only a few thousand or maybe tens of thousands of flowers, and they probably opened and closed in pretty good synchronization, meaning none of the flowers were receptive to pollen (female) at the same time that other flowers were shedding pollen (male).

You could either plant or graft onto it a compatible variety with the opposite flowering pattern, or manually collect pollen when the flowers are in male phase, and hand pollinate later that day or early the next day when all the new flowers open in female phase. The problem is there’s too much time between those phases, so none of the pollinators still have the pollen on them at the right time.

When your tree gets much larger, it will probably become a continuous cloud of pollen even 12 hours after the male -phase flowers close up shop, so I bet you’ll see fruit setting then.

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This is really interesting re: Lula’s lack of cold hardiness.

I know the guy who has the Millennial Gardener channel on Youtube has a four or five year old Lula he’s been growing in ground over in Wilmington NC. I know he uses a lot of winter protection, but he must be doing way more than I thought if he’s kept it alive so far.

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Are you sure it’s not “Lila”? That’s a hardy cultivar more suitable for zone pushing.

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Ah, it’s probably Lila then.

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This Duke seedling has still not shed its original leaves from last season, though a couple of the oldest are starting to yellow finally:

It makes it hard to try to photograph the base to show where the frost damage starts, but you can kind of see it here:

It has been continuously flushing so far since it started in the spring, no sign of periodic flushes like most other avocados. Looks like it’s about to get bushy again at the top, I love to see this because I think the bushiness is a big part of what protected the base:

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I’d like to have some Duke and Avravaipa scions too

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Where are you located @CherryLover1? This isn’t a good time of year for grafting in most locations, unless you’ll be keeping them indoors all winter. I’ve had some success bench grafting avocados in late summer and keeping them in a heated greenhouse, but usually the early spring grafts catch up with them the next year anyhow.

I have plenty of spare Duke scions, could probably spare one scion of Aravaipa, but if you’re in CA then probably are limited to sources within CA due to the state’s rules regarding import of avocado plant material. Feel free to PM me rather than discussing here in thread.

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I am in So. California, darn. I guess I have to wait for someone in California. Thank you for kindness though. I am planning to graft in next year Spring, so I don’t need them right now. I have some rootsotcks growing.

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Fruitwood nursery in northwestern california is a good source for scion wood.

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Fruitwood is great, but they don’t carry Duke. @Marta’s Really Good Plants website was basically the only online place to buy Duke scions, and she has moved away from the online store model, just holding occasional brief sales instead. I don’t think she even included Duke in the last sale this March.

For anyone in northern CA with a car and an afternoon to spare, your best option is probably to drive to Oroville and collect some scions from the old train station tree directly. But that would be a bit of a road trip from So Cal!

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I don’t know any other nurseries than fruitwood. It’s the place where I ordered my scions. I know they had duke on their online shop two years ago.
Maybe you’'d have to ask per email.

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They have “Duke7” which is a seedling of Duke that was selected by UC researchers in a rootstock program long ago, but Duke7 is not the same as Duke.

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Do you know the difference in hardiness, fruit quality or in generel?

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I don’t, I haven’t grown Duke7 myself. I have grown a couple dozen seedlings of Duke, though, and they are remarkably uniform in phenotype, so unless Duke7 was cross-pollinated (it was open pollinated, so UC didn’t know the pollen parent), I’d expect it to be pretty similar to Duke in most characteristics. None of mine have fruited, though, so I’m not sure if fruit characteristics of the seedlings are as uniform as leaf/stem/growth habit.

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Unfortunately I didn’t graft Duke onto my home tree. After moving my collection from one location to another, I need to reestablish my Duke. For Aravaipa, I should have plenty of scions in December (if anyone wants to graft in winter) and in March on my sales site reallygoodplants.com I will not have any fruits for sale as the harvest is pretty low to none on the fall ripening (and others) cultivars due to the wet cold spring we had. Here is the harvest report https://youtube.com/shorts/9wMVSZIog8w?si=WCjIlttPSF_nAHRe

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