where to buy cold hardy avocado trees in northern Ca?

[Lyn38]

I've looked all over online and am having a hard time finding any nursery or person who sells cold hardy avos for a reasonable price. I found one that sells both Lila and Joey, but they're on bacon rootstocks which doesn't sound viable in my area. I'm in a coastal zone 8b.

[aaronn]

You could try Epicenter
https://www.epicenteravocados.com/

[Lyn38]

Thanks Aaronn, I did. They don't have any cold hardy ones except Bonny Doon, which I was curious about because I lived in Bonny Doon once. Another poster on here said it never really frosted hard where the tree was. ?? Maybe it's very near buildings ?? So not sure about that one.

[Bush2Beach]

Bonny Soon mother tree is near Safeway on Mission Street so right by the Ocean an not more cold tolerant.

Bacon is a fine rootstock for you.

I think those are Florida Avocado's, Plant some Cold hardy Mexican varieties , plenty of searchable info on this site for which kinds,

[Lyn38]

Bush2Beach, I think that's where Epicenter nursery is. The original mother tree, where they got their mother, is supposed to be up in Bonny Doon. But it may be near a building..

I'm a warmer 8 so yes, I'm limited to Mexican varieties. BD might not be cold hardy enough. I was really interested in it because I used to live up there a long time ago. But, not really practical for me unless I graft it and then just heat the one branch or something, lol. Not practical..

I'm having a hard time finding nurseries that carry smaller Mexican varieties like Fantastic, Joey, Lila etc.

Most of the Texas nurseries will not ship to California. I'd rather travel to SC or Sac to pick one up anyway.

Bacon won't work here as a root stock- not hardy enough. But Mexican varieties are used as root stocks anyway. I'm probably better off with a rooted cutting. I wonder if a cutting is likely to root after it's been in the mail for a week?

[Bush2Beach]

Your incorrect. The mother Bonny Soon tree is not in Bonny Doon.
It is located next to what used to be the Bonny Soon Winery Tasting Room, Almar and Fair St. , blocks from the Ocean in Santa Cruz.
Epicenter is in La Selva Beach, Your better off buying Avocado tree's from elsewhere.

You have a hard time finding those Florida Avocado's because in CA the nurseries are full of CA varieties.

Avocado grown from cutting? You really lost me now.

direct seed and graft since they likely will not survive anyhow.

Bush2Beach, I think that's where Epicenter nursery is. The original mother tree, where they got their mother, is supposed to be up in Bonny Doon. But it may be near a building..

I'm a warmer 8 so yes, I'm limited to Mexican varieties. BD might not be cold hardy enough. I was really interested in it because I used to live up there a long time ago. But, not really practical for me unless I graft it and then just heat the one branch or something, lol. Not practical..

I'm having a hard time finding nurseries that carry smaller Mexican varieties like Fantastic, Joey, Lila etc.

Most of the Texas nurseries will not ship to California. I'd rather travel to SC or Sac to pick one up anyway.

Bacon won't work here as a root stock- not hardy enough. But Mexican varieties are used as root stocks anyway. I'm probably better off with a rooted cutting. I wonder if a cutting is likely to root after it's been in the mail for a week?

[Owen H]

Fruitwood nursery sells scions of several cold hardy varieties. As far as rootstock goes, you can probably find some mexicola or mexicola grande seeds on this board in season.

[drymifolia]

Avocado grown from cutting? You really lost me now.
direct seed and graft since they likely will not survive anyhow.

It is possible (not easy) to root avocado cuttings, especially Mexican types (which root easier than Guatemalan or WI types), but not if you use scions that you can buy for grafting. You need intact leaves and lots of patience, and a large number of them because success rates are low.

To root an avocado cutting, you should take about 5 inches of nearly-hardened growth at the end of a flush, trim the lower leaves and cut out the bud sites that will be below ground (roots will form on callus, buds might otherwise swell, steal energy, and rot). Leave at least 2-3 leaves, though they can be trimmed a bit if they are too large. Plant in potting mix, and provide intermittent mist & humidity control for 6+ months, removing any that wilt. Then, baby them for another year because their roots will be weak initially and easy to kill. Maybe 3 years later you'll have a small plant about the size of a 6-month seedling.

Seeds are a much better option, grow for a year or two, and graft onto any that survive the winter. Seeds should be available from CA members on this forum from late summer through the fall. Do not import plants from FL or TX even if you find members willing, the longer laurel wilt stays out of CA the better! It'll get there eventually, but no need to accelerate.

[Lyn38]

Your incorrect. The mother Bonny Soon tree is not in Bonny Doon.
It is located next to what used to be the Bonny Soon Winery Tasting Room, Almar and Fair St. , blocks from the Ocean in Santa Cruz.
Epicenter is in La Selva Beach, Your better off buying Avocado tree's from elsewhere.

You have a hard time finding those Florida Avocado's because in CA the nurseries are full of CA varieties.

Avocado grown from cutting? You really lost me now.

direct seed and graft since they likely will not survive anyhow.

Well, you're right about Bonny Doon Vinyard's tasting room. It's not in Bonny Doon, it appears to be in Aptos now, and may have been in SC. On everything else your not only wrong, but rude. There are several trees growing in my broader area. I didn't mention any Florida varieties. And people do root cuttings, although it's difficult.

[Lyn38]

Fruitwood nursery sells scions of several cold hardy varieties. As far as rootstock goes, you can probably find some mexicola or mexicola grande seeds on this board in season.

Thanks Owen!It's probably more practical to grow a rootstock out and later graft to it. I'd like to try both, although, I generally root any sort of cuttings immediately after cutting. I don't know if woody cuttings would still be rootable after mailing  ??

Oh!! Fruitwood on the Klamath? Wow, If they own some of the mothers I could possibly buy it as they cut. I go up that way every now and then, not very far from me. Thank you, very helpful!

[Lyn38]

Avocado grown from cutting? You really lost me now.
direct seed and graft since they likely will not survive anyhow.

It is possible (not easy) to root avocado cuttings, especially Mexican types (which root easier than Guatemalan or WI types), but not if you use scions that you can buy for grafting. You need intact leaves and lots of patience, and a large number of them because success rates are low.

To root an avocado cutting, you should take about 5 inches of nearly-hardened growth at the end of a flush, trim the lower leaves and cut out the bud sites that will be below ground (roots will form on callus, buds might otherwise swell, steal energy, and rot). Leave at least 2-3 leaves, though they can be trimmed a bit if they are too large. Plant in potting mix, and provide intermittent mist & humidity control for 6+ months, removing any that wilt. Then, baby them for another year because their roots will be weak initially and easy to kill. Maybe 3 years later you'll have a small plant about the size of a 6-month seedling.

Seeds are a much better option, grow for a year or two, and graft onto any that survive the winter. Seeds should be available from CA members on this forum from late summer through the fall. Do not import plants from FL or TX even if you find members willing, the longer laurel wilt stays out of CA the better! It'll get there eventually, but no need to accelerate.

Drymifolia, thank you!  Seedling rootstock does sound like a better idea. Owen mentioned a nursery near me that sells scions and if they have mothers I might try both methods. I root a lemon's cuttings some years and it sometimes takes over 6 months to root. It's a major PITA and a lot of them die before rooting. I'm going to try air layering it this year instead, and I ordered some trifoliate seeds for citrus rootstock..

And thank you, I won't order anything from out Texas or Fla. Does Az have that problem as well? I might want to try Aravaipa as rootstock, not sure if it's readily available in Ca. but if it's chancy I won't..

[Bush2Beach]

Hey, no shit? . I tried telling you the first time around , it didn’t take. Good luck with your unrealistic plant puttering.
Telling you your Avocados will likely die in your location is reality , not rude dude.

Your incorrect. The mother Bonny Soon tree is not in Bonny Doon.
It is located next to what used to be the Bonny Soon Winery Tasting Room, Almar and Fair St. , blocks from the Ocean in Santa Cruz.
Epicenter is in La Selva Beach, Your better off buying Avocado tree's from elsewhere.

You have a hard time finding those Florida Avocado's because in CA the nurseries are full of CA varieties.

Avocado grown from cutting? You really lost me now.

direct seed and graft since they likely will not survive anyhow.

Well, you're right about Bonny Doon Vinyard's tasting room. It's not in Bonny Doon, it appears to be in Aptos now, and may have been in SC. On everything else your not only wrong, but rude. There are several trees growing in my broader area. I didn't mention any Florida varieties. And people do root cuttings, although it's difficult.

[drymifolia]

And thank you, I won't order anything from out Texas or Fla. Does Az have that problem as well? I might want to try Aravaipa as rootstock, not sure if it's readily available in Ca. but if it's chancy I won't..

Last year Marta sold Aravaipa fruit boxes when they were in season, she's in northern CA and her website is here, though I'm not sure if she plans to do the same this year:
https://reallygoodplants.com/

Another option for you, if you can get to Oroville, is to collect scions (or fruit in the fall) from the Duke tree in the parking lot of the old train station (I believe it's a restaurant now). Or, if you know of any trees that seem to be doing well in your area, knock on their door and ask about them. Most people are happy to share cuttings, and they may have seedlings growing in their yard that you could dig up.

I will echo Bush2Beach in one respect, though: be ready to kill most avocados you try to grow. I'm a couple years into my project here and I've definitely killed more trees than have survived. But Duke and Aravaipa both show promise, and so do some lesser known varieties I got from the UC Research Grove, like Northrup.

But even with hints of success, I'm expecting it will take thousands of seedlings to find even just a couple that can handle my cool 8b that borders on 9a, but is in sunset zone 4. What is your sunset zone?

[Lyn38]

And thank you, I won't order anything from out Texas or Fla. Does Az have that problem as well? I might want to try Aravaipa as rootstock, not sure if it's readily available in Ca. but if it's chancy I won't..

Last year Marta sold Aravaipa fruit boxes when they were in season, she's in northern CA and her website is here, though I'm not sure if she plans to do the same this year:
https://reallygoodplants.com/

Another option for you, if you can get to Oroville, is to collect scions (or fruit in the fall) from the Duke tree in the parking lot of the old train station (I believe it's a restaurant now). Or, if you know of any trees that seem to be doing well in your area, knock on their door and ask about them. Most people are happy to share cuttings, and they may have seedlings growing in their yard that you could dig up.

I will echo Bush2Beach in one respect, though: be ready to kill most avocados you try to grow. I'm a couple years into my project here and I've definitely killed more trees than have survived. But Duke and Aravaipa both show promise, and so do some lesser known varieties I got from the UC Research Grove, like Northrup.

But even with hints of success, I'm expecting it will take thousands of seedlings to find even just a couple that can handle my cool 8b that borders on 9a, but is in sunset zone 4. What is your sunset zone?

I'm in Sunset zone 15. 8b bordering on 9a but am in a low elevation warmer microclimate surrounded by buildings that don't have very good insulation so quite a bit of heat leakage. I'm estimating that adds 3-5 degrees, and another degree or so on my covered deck, although I don't have an outside thermometer. I need to get one.. I'm hoping to move and if so would be building a small greenhouse with a heat retention wall. What makes it an 8b is the "record" lows every 10 years or so. There really aren't any records I can find so far for extreme lows in this town..

Yep. I anticipate killing some plants. And using xmass lights. Won't be the first time. Just trying to figure out a way to kill less of them. Although, I'm wondering if it's worth it without a greenhouse. I keep seeing feedback that the Mexican avos taste bad except the mexicola grande and those would be very hard to keep small.

[Lyn38]

And thank you, I won't order anything from out Texas or Fla. Does Az have that problem as well? I might want to try Aravaipa as rootstock, not sure if it's readily available in Ca. but if it's chancy I won't..

Last year Marta sold Aravaipa fruit boxes when they were in season, she's in northern CA and her website is here, though I'm not sure if she plans to do the same this year:
https://reallygoodplants.com/

Another option for you, if you can get to Oroville, is to collect scions (or fruit in the fall) from the Duke tree in the parking lot of the old train station (I believe it's a restaurant now). Or, if you know of any trees that seem to be doing well in your area, knock on their door and ask about them. Most people are happy to share cuttings, and they may have seedlings growing in their yard that you could dig up.

I will echo Bush2Beach in one respect, though: be ready to kill most avocados you try to grow. I'm a couple years into my project here and I've definitely killed more trees than have survived. But Duke and Aravaipa both show promise, and so do some lesser known varieties I got from the UC Research Grove, like Northrup.

But even with hints of success, I'm expecting it will take thousands of seedlings to find even just a couple that can handle my cool 8b that borders on 9a, but is in sunset zone 4. What is your sunset zone?

I'm in Sunset zone 15. 8b bordering on 9a but am in a low elevation warmer microclimate surrounded by buildings that don't have very good insulation so quite a bit of heat leakage. I'm estimating that adds 3-5 degrees, and another degree or so on my covered deck, although I don't have an outside thermometer. I need to get one.. I'm hoping to move and if so would be building a small greenhouse with a heat retention wall. What makes it an 8b is the "record" lows every 10 years or so. There really aren't any records I can find so far for extreme lows in this town..

Yep. I anticipate killing some plants. And using xmass lights. Won't be the first time. Just trying to figure out a way to kill less of them. Although, I'm wondering if it's worth it without a greenhouse. I keep seeing feedback that the Mexican avos taste bad except the mexicola grande and those would be very hard to keep small.

& thanks, I contacted one grower and there is another I've heard of and am putting the word out. It might take months to get to contact that one. The few others are a little warmer than me..

I suspect you have a greenhouse.. But, I also suspect you've grown a lot of the Mexican cultivators in your 8b zone.. I'm beginning to think that a lot of the Mexican cultivators have random seedling mothers mixed in. Like, someone may have grown out a seed from Joey and then called it Joey and passed it around and eventually it got sold?? do you think that might be the case? I know taste is different for different people, but I'm seeing very drastic differences of opinions on the taste of Mexican varieties. And after reading the very long post on avos 24/7 I see a couple mentions of variability in individuals of the same variety ?? Including recently from you. ??

[drymifolia]

I suspect you have a greenhouse.. But, I also suspect you've grown a lot of the Mexican cultivators in your 8b zone.. I'm beginning to think that a lot of the Mexican cultivators have random seedling mothers mixed in. Like, someone may have grown out a seed from Joey and then called it Joey and passed it around and eventually it got sold?? do you think that might be the case? I know taste is different for different people, but I'm seeing very drastic differences of opinions on the taste of Mexican varieties. And after reading the very long post on avos 24/7 I see a couple mentions of variability in individuals of the same variety ?? Including recently from you. ??

I think environmental differences account for a big part of the variation, but also I think people often will say that two varieties are "the same" based on visual similarity of the fruit, rather than actual knowledge they are the same, as I suspect is the case with Fantastic & Del Rio.

Mexican avocados do poorly in most of Florida due to the thin skins allowing them to rot or get damaged more easily. Some people may also leave them on the tree too long, when their consistency and flavor begin to deteriorate.

There may also be an epidemic of mislabeled trees from some online nurseries (e.g., Fast Growing Trees sent me two trees that were definitely not Poncho or Brazos Belle, they weren't even Mexican avocados).

As far as flavor, Mexicola is a very good (very small) avocado. It may not be as hardy as some others, but it should be available from most CA nurseries, and it's worth a try. Duke is also good, with the tree in Oroville publicly accessible if you can't find anyone selling them. I might have scions next winter, if you want it then.

And yes, I have a greenhouse, but have also been planting out many seedlings and grafted trees to test the claims of hardiness. The project is still in the early years, though, the greenhouse trees are only 2-3 years in the ground at the oldest. I'm hoping next year they will be large enough to start producing seeds for the project.

[Lyn38]

I suspect you have a greenhouse.. But, I also suspect you've grown a lot of the Mexican cultivators in your 8b zone.. I'm beginning to think that a lot of the Mexican cultivators have random seedling mothers mixed in. Like, someone may have grown out a seed from Joey and then called it Joey and passed it around and eventually it got sold?? do you think that might be the case? I know taste is different for different people, but I'm seeing very drastic differences of opinions on the taste of Mexican varieties. And after reading the very long post on avos 24/7 I see a couple mentions of variability in individuals of the same variety ?? Including recently from you. ??

I think environmental differences account for a big part of the variation, but also I think people often will say that two varieties are "the same" based on visual similarity of the fruit, rather than actual knowledge they are the same, as I suspect is the case with Fantastic & Del Rio.

Mexican avocados do poorly in most of Florida due to the thin skins allowing them to rot or get damaged more easily. Some people may also leave them on the tree too long, when their consistency and flavor begin to deteriorate.

There may also be an epidemic of mislabeled trees from some online nurseries (e.g., Fast Growing Trees sent me two trees that were definitely not Poncho or Brazos Belle, they weren't even Mexican avocados).

As far as flavor, Mexicola is a very good (very small) avocado. It may not be as hardy as some others, but it should be available from most CA nurseries, and it's worth a try. Duke is also good, with the tree in Oroville publicly accessible if you can't find anyone selling them. I might have scions next winter, if you want it then.

And yes, I have a greenhouse, but have also been planting out many seedlings and grafted trees to test the claims of hardiness. The project is still in the early years, though, the greenhouse trees are only 2-3 years in the ground at the oldest. I'm hoping next year they will be large enough to start producing seeds for the project.

Thanks. I will also tell the people I talked to today. The people growing avos north of me are also interested in Duke and in finding other hardy seeds and hopefully one of us can make it out there when Duke is fruiting and at least get a few. Any idea when that might be? I think I won't have anything to graft to this year. I'm thinking I definitely want to find hardy varieties for rootstock first. Zutano etc isn't going to work long term outside here.

Aravaipa sounds like a better option for rootstock to me, if things will take to it. That's another one that someone said tasted actually horrid, while the folks at Epicenter in Santa Cruz said it was pretty good (maybe bland).

I think there might be an epidemic of mislabeled stuff. I live in Humboldt county and I know first hand that a lot of the other kinds of plants grown here were mislabeled over the decades. I've watched people do it. People would just make up names when they couldn't figure it out or lost the tags. Frosted-rainbow-diesel-unicorn-cookies or whatever. Or readily sell clones under a different name if it would sell better. Plus most people "breeding" here didn't understand what "phenotype" meant.

Plus, same, many people who grow avo pits on their windowsills are convinced it's the same thing, which has to be a good percentage of what you'd get that's been left in a canyon for 100 years or randomly growing in a cold backyard..

Oh! And if you have a very good tasting Mexicola then that is a wood I would really really like from you in the future. I would have a good idea that it really is a Mexicola!

And do you think any seeds from Mexican varieties that fruited this winter or last fall might still be viable? Sorry, I am really picking your brain here, but I'm completely new to avos.

[Lyn38]

I suspect you have a greenhouse.. But, I also suspect you've grown a lot of the Mexican cultivators in your 8b zone.. I'm beginning to think that a lot of the Mexican cultivators have random seedling mothers mixed in. Like, someone may have grown out a seed from Joey and then called it Joey and passed it around and eventually it got sold?? do you think that might be the case? I know taste is different for different people, but I'm seeing very drastic differences of opinions on the taste of Mexican varieties. And after reading the very long post on avos 24/7 I see a couple mentions of variability in individuals of the same variety ?? Including recently from you. ??

I think environmental differences account for a big part of the variation, but also I think people often will say that two varieties are "the same" based on visual similarity of the fruit, rather than actual knowledge they are the same, as I suspect is the case with Fantastic & Del Rio.

Mexican avocados do poorly in most of Florida due to the thin skins allowing them to rot or get damaged more easily. Some people may also leave them on the tree too long, when their consistency and flavor begin to deteriorate.

There may also be an epidemic of mislabeled trees from some online nurseries (e.g., Fast Growing Trees sent me two trees that were definitely not Poncho or Brazos Belle, they weren't even Mexican avocados).

As far as flavor, Mexicola is a very good (very small) avocado. It may not be as hardy as some others, but it should be available from most CA nurseries, and it's worth a try. Duke is also good, with the tree in Oroville publicly accessible if you can't find anyone selling them. I might have scions next winter, if you want it then.

And yes, I have a greenhouse, but have also been planting out many seedlings and grafted trees to test the claims of hardiness. The project is still in the early years, though, the greenhouse trees are only 2-3 years in the ground at the oldest. I'm hoping next year they will be large enough to start producing seeds for the project.

Oh, and yes, if I find or gather any duke seeds I will definitely try and get at least one extra for you, if not more. I can probably get some seeds from unnamed varieties in the area of Fort Bragg Ca, although I don't know yet if any of them are further inland. They may not be that hardy if right near the ocean. There may be another further north and inland but I have to find it out.

[drymifolia]

I haven't visited the Oroville Duke tree in season, but my understanding is it starts to ripen in early fall, Sept/Oct, the same time Duke grafts ripen in other parts of northern CA. I don't think I'll need any more Duke seeds this fall, but thank you for the offer.

Aravaipa and Duke both make good rootstocks. I thought Aravaipa tasted OK when I got a box from Marta, but bland, and when counter ripening they quickly go from underripe to overripe, with only a day or two to eat them at peak ripeness. I assume the people who thought they were gross let them get overripe or picked them too soon or too late.

My Mexicola graft is very recent, the fruit I've eaten were from Marta and Mexican markets in the SF bay area. Fruitwood Nursery has Mexicola scions, that's where mine came from. I recommend signing up on their website to be notified when scions you're interested in are in stock. Their avocado scionwood usually is only in stock for a week or two in late fall or early winter.

As far as seeds from last fall still being viable, any that haven't molded or dried out might still sprout if they've been kept in a fridge drawer or something, but most seed sellers on places like Etsy and eBay are not trustworthy and mostly sell mislabeled seeds.

[Reedo]

Marta has done some work trialing and evaluating some cold hardy varieties. She's growing in Davis, CA. She doesn't sell plants, but occasionally sells scions on her reallygoodplants site.  I've tasted Mexicola (not to be confused with Mexicola Grande), and it's quite good. It takes more work to process due to its thin, non-peeling skin, but it's a small price to pay for fresh homegrown avocados. I believe you can find this trees at nurseries, but you'd probably benefit from grafting it onto a more cold-hardy rootstock than what Brokaw uses.

https://fruitsandgardening.blogspot.com/2020/03/cold-hardy-avocados-for-sacramento.html

https://fruitsandgardening.blogspot.com/2020/03/cold-hardy-avocados-for-sacramento.html

https://fruitsandgardening.blogspot.com/2023/01/john-herd-and-sir-prize-avocados.html

https://reallygoodplants.com/

[Enkis]

I've read it's possible to use cold sensitive rootstock if you graft low and then plant the tree deeper, so that the joint is below ground. As anyone tried this? Any idea how much deep it should be planted?

[Lyn38]

I've read it's possible to use cold sensitive rootstock if you graft low and then plant the tree deeper, so that the joint is below ground. As anyone tried this? Any idea how much deep it should be planted?

Enkis, I've never grown out avocado but I would guess to plant the rootstock below the level of soil temperature that the rootstock is hardy to, and then mulch it thickly. Mulch can keep the soil warmer by several degrees. Keep the soil at that level well drained - like a mound. Seems like it would work well in other than very marginal climates. If you only get very low temps for short periods of time - like several hours or once in a while overnight, with temps increasing during the day then it should work. IDK about longer low temps - like days on end. That tends to cool the soil down more.

EDIT you would probably get a few degrees more cold hardiness from a cold hardy root stock though, is my guess, as there would less chance of stressing the root system.

[Lyn38]

I haven't visited the Oroville Duke tree in season, but my understanding is it starts to ripen in early fall, Sept/Oct, the same time Duke grafts ripen in other parts of northern CA. I don't think I'll need any more Duke seeds this fall, but thank you for the offer.

Aravaipa and Duke both make good rootstocks. I thought Aravaipa tasted OK when I got a box from Marta, but bland, and when counter ripening they quickly go from underripe to overripe, with only a day or two to eat them at peak ripeness. I assume the people who thought they were gross let them get overripe or picked them too soon or too late.

My Mexicola graft is very recent, the fruit I've eaten were from Marta and Mexican markets in the SF bay area. Fruitwood Nursery has Mexicola scions, that's where mine came from. I recommend signing up on their website to be notified when scions you're interested in are in stock. Their avocado scionwood usually is only in stock for a week or two in late fall or early winter.

As far as seeds from last fall still being viable, any that haven't molded or dried out might still sprout if they've been kept in a fridge drawer or something, but most seed sellers on places like Etsy and eBay are not trustworthy and mostly sell mislabeled seeds.

Thanks Drymifolia! I now have a whole section of notes with info from you. Have copied and saved the info. Much appreciated.

[Lyn38]

Marta has done some work trialing and evaluating some cold hardy varieties. She's growing in Davis, CA. She doesn't sell plants, but occasionally sells scions on her reallygoodplants site.  I've tasted Mexicola (not to be confused with Mexicola Grande), and it's quite good. It takes more work to process due to its thin, non-peeling skin, but it's a small price to pay for fresh homegrown avocados. I believe you can find this trees at nurseries, but you'd probably benefit from grafting it onto a more cold-hardy rootstock than what Brokaw uses.

https://fruitsandgardening.blogspot.com/2020/03/cold-hardy-avocados-for-sacramento.html

https://fruitsandgardening.blogspot.com/2020/03/cold-hardy-avocados-for-sacramento.html

https://fruitsandgardening.blogspot.com/2023/01/john-herd-and-sir-prize-avocados.html

https://reallygoodplants.com/

Thanks Reedo! Appreciate the feedback and info. It looks like Marta is a great person to try and get material from. I'll bet she runs out, so maybe I'll try and get just 3-5 Aravaipa seeds/fruit and maybe some Mexicola or Mexicola Grande fruit from her this fall if she has it. Those varieties might make good rootstock as well and are more common so I can leave them out on my deck after growing a bit and see which do the best.

[drymifolia]

I've read it's possible to use cold sensitive rootstock if you graft low and then plant the tree deeper, so that the joint is below ground. As anyone tried this? Any idea how much deep it should be planted?

I've tried this and it has not worked, but the soil temperatures can be pretty cold here in Seattle by end of winter. 4 year old West Indies rootstocks (Lula seedlings) have completely died even when the graft union is buried, even where the grafted variety on top survived initially (until it realized its roots were dead weeks later). But I assume something like Bacon or Zutano might work fine as long as you cover the graft union with soil or mounded wood chips.