Author Topic: Cold Hardy Avocado Rootstock  (Read 1307 times)

Va Beach Grower

  • Member
  • ***
  • Posts: 39
    • USA, VA, Virginia Beach, 8A
    • View Profile
Cold Hardy Avocado Rootstock
« on: January 26, 2023, 04:18:42 PM »
Please check my logic on this, but I'm looking for avocado rootstock, and seems like only 1 place has it.  I'm trying to grow Avocado trees in Va Beach, and it looks like most online cold hardy avocado's maybe don't say what rootstock is used, or you can't find rootstock that is the most cold hardy (like Del Rio or Mexicola or something).  So, would it be easier to just buy the most cold  hardy avocado's online (Del Rio), save the seeds and start growing from seed, then get other scion to graft onto these?  I realize it'll take maybe a year to grow rootstock from seed, but I figure if commercially they typically graft to Zutano, is it better to start with the most cold hardy avocado's to use for rootstock, or maybe those kind of rootstock cause all sorts of different problems?  Please educate me :)

Bonus points if you can give me a link of a place where I can buy a dozen Del Rio Avocado's or other cold hardy ones online.  Thanks!


TREESNMORE

  • Hero Member
  • *****
  • Posts: 1034
    • USA Palm City FL Zone 10a
    • View Profile
Re: Cold Hardy Avocado Rootstock
« Reply #1 on: January 26, 2023, 05:00:31 PM »
It will not take a year to grow out your seedlings . You graft avocado seedling when young about 6 inches and new growth .
Mike

drymifolia

  • Hero Member
  • *****
  • Posts: 619
    • Seattle 9a/sunset zone 5
    • View Profile
    • the drymifolia collective
Re: Cold Hardy Avocado Rootstock
« Reply #2 on: January 26, 2023, 06:42:12 PM »
Bonus points if you can give me a link of a place where I can buy a dozen Del Rio Avocado's or other cold hardy ones online.  Thanks!

I've never found a reliable commercial source of the allegedly hardiest Mexican avocados, as either fruit or seeds.

I've been very happy with the size and health of avocado rootstocks from Fruitwood Nursery, but they only offer Zutano and Bacon, neither of which is really all that hardy (Bacon is probably fine if you graft low, though).
https://www.fruitwoodnursery.com/fruit-tree-scion-and-cuttings-wood/avocado-scionwood

Marta sells boxes of fruit sometimes when they are in season, I bought a box of Aravaipa from her in the fall and they came in great shape, but it's the wrong time of year now. Here's her store though, it says she will add stuff again in March, that's probably just scionwood though unless she decides to sell Royal-Wright fruit:
https://reallygoodplants.com/

Miami Fruit sells Mexicola boxes, but they definitely aren't cheap.
https://miamifruit.org/products/mexicola-avocado-box-pre-order

This Etsy seller looks like they have pretty good reviews, but I've never bought from them, Fuerte is fairly hardy:
https://www.etsy.com/listing/1381581856/8-count-fresh-organic-fuerte-avocados
« Last Edit: January 26, 2023, 07:37:27 PM by drymifolia »

drymifolia

  • Hero Member
  • *****
  • Posts: 619
    • Seattle 9a/sunset zone 5
    • View Profile
    • the drymifolia collective
Re: Cold Hardy Avocado Rootstock
« Reply #3 on: January 26, 2023, 07:09:12 PM »
It will not take a year to grow out your seedlings . You graft avocado seedling when young about 6 inches and new growth .

I've done it both ways, and I find it easier to graft on 1 year seedlings because the stem is less delicate, and matches the diameter of most scions better for cleft grafts. Though I've had good results both ways for sure.

My main reason I graft later (near 1 year at least) is I'm letting pretty much all the rootstocks grow their own branch to also be evaluated for hardiness in our project, so grafting a little higher helps on that front.

Va Beach Grower

  • Member
  • ***
  • Posts: 39
    • USA, VA, Virginia Beach, 8A
    • View Profile
Re: Cold Hardy Avocado Rootstock
« Reply #4 on: January 27, 2023, 08:04:38 AM »
It will not take a year to grow out your seedlings . You graft avocado seedling when young about 6 inches and new growth .

I've done it both ways, and I find it easier to graft on 1 year seedlings because the stem is less delicate, and matches the diameter of most scions better for cleft grafts. Though I've had good results both ways for sure.

My main reason I graft later (near 1 year at least) is I'm letting pretty much all the rootstocks grow their own branch to also be evaluated for hardiness in our project, so grafting a little higher helps on that front.

Do you ever try to root your own cuttings from hardy trees?  So maybe you have 1 tree that the branches have done really well and you want to replicate that tree but w/the rootstock, or just a copy of that tree all together?  Or even air layering?  I'm just wondering if rootstock being less cold hardy is a problem, are people not using cold hardy rootstock (or just cloning a tree all together and not using rootstock to graft at all) for another reason?  I know certain rootstock is easier to grow than others and probably more disease resistant, but w/cold hardy avocado's being more popular, is there not a standard cold hardy rootstock that is being used normally?

drymifolia

  • Hero Member
  • *****
  • Posts: 619
    • Seattle 9a/sunset zone 5
    • View Profile
    • the drymifolia collective
Re: Cold Hardy Avocado Rootstock
« Reply #5 on: January 27, 2023, 12:12:00 PM »
Do you ever try to root your own cuttings from hardy trees?  So maybe you have 1 tree that the branches have done really well and you want to replicate that tree but w/the rootstock, or just a copy of that tree all together?  Or even air layering?  I'm just wondering if rootstock being less cold hardy is a problem, are people not using cold hardy rootstock (or just cloning a tree all together and not using rootstock to graft at all) for another reason?  I know certain rootstock is easier to grow than others and probably more disease resistant, but w/cold hardy avocado's being more popular, is there not a standard cold hardy rootstock that is being used normally?

Yes, I've been tweaking my process for rooting cuttings for a little over a year now, and my success percentage is improving but it's still very slow (6+ months to root, slow growth for a year). Here are my current rooting clones:

https://www.drymifolia.org/trees.php?subset=rooted

And as to the second question -- a standard rootstock for hardy avocados -- all the nurseries I'm aware of that propagate hardy avocados are in less marginal areas where the hardiness of the rootstock doesn't matter as much as whether it's disease resistant and well-adapted to local soils.  Most nurseries that propagate avocados intended for retail customers just use the same rootstock for all their avocados, hardy and otherwise, because that's easiest for them.
« Last Edit: January 27, 2023, 12:27:31 PM by drymifolia »

Va Beach Grower

  • Member
  • ***
  • Posts: 39
    • USA, VA, Virginia Beach, 8A
    • View Profile
Re: Cold Hardy Avocado Rootstock
« Reply #6 on: January 27, 2023, 02:23:15 PM »
Do you ever try to root your own cuttings from hardy trees?  So maybe you have 1 tree that the branches have done really well and you want to replicate that tree but w/the rootstock, or just a copy of that tree all together?  Or even air layering?  I'm just wondering if rootstock being less cold hardy is a problem, are people not using cold hardy rootstock (or just cloning a tree all together and not using rootstock to graft at all) for another reason?  I know certain rootstock is easier to grow than others and probably more disease resistant, but w/cold hardy avocado's being more popular, is there not a standard cold hardy rootstock that is being used normally?

Yes, I've been tweaking my process for rooting cuttings for a little over a year now, and my success percentage is improving but it's still very slow (6+ months to root, slow growth for a year). Here are my current rooting clones:

https://www.drymifolia.org/trees.php?subset=rooted

And as to the second question -- a standard rootstock for hardy avocados -- all the nurseries I'm aware of that propagate hardy avocados are in less marginal areas where the hardiness of the rootstock doesn't matter as much as whether it's disease resistant and well-adapted to local soils.  Most nurseries that propagate avocados intended for retail customers just use the same rootstock for all their avocados, hardy and otherwise, because that's easiest for them.

What do you have the most success with when rooting cuttings?  I am currently rooting some figs from a neighbor who gave me cuttings (those are super easy, throw in a moist paper towel in a ziplock bag and throw it in the closet for a few weeks) and am also going to try rooting apple and peach tree cuttings the same way (and via some growing medium w/bags on top) and am currently trying to do some blueberries as well.  I know each fruit probably needs it's own spin, but I saw a video where they did the cuttings, removed all but the top 4-5 leaves and then cut them in half, then put in medium and bag on top and then left it alone for a while.  The video's all make it look so easy but I imagine it's quite challenging.  I'm experimenting w/blueberry cuttings and trying in different mediums (sand, peat, peat/perlite mix and mel's mix as well as paper towel method in a bag to see what the results are).  Anyways, trying to take some lesson's learned as I know you're in deep into your experimentation, and I don't see on your website where how you are rooting cuttings, but would love to give it a whurl.  Can you do it w/scion (w/o leaves) or do you need the leaves on to keep the plant alive?

drymifolia

  • Hero Member
  • *****
  • Posts: 619
    • Seattle 9a/sunset zone 5
    • View Profile
    • the drymifolia collective
Re: Cold Hardy Avocado Rootstock
« Reply #7 on: January 27, 2023, 05:06:00 PM »
I could probably write an opus on my attempts to root avocado cuttings. There are also some good old journal articles on this question, where they found that Mexican avocados rooted much more easily than Guatemalan (intermediate success) or West Indian (almost zero success), but it can take many months to root. Based on those studies and my own testing of methods, this is what has worked best:

1) Cut the branch tips right near the end of a flush (done expanding but not done hardening), removing at least 5-6 inches. This works best if the bottom of what you remove has finished hardening (firm stem) even if the new leaves at the tip have not.

2) Trim off all leaves except the smallest 2-3, and remove the dormant buds next to the lower leaves, too (roots only form on callus, not from bud sites, which might rot).

3) (optional) I now store those prepared cuttings in the back of an aquarium filter (filter media removed) until they form nice bumpy callus (a couple weeks). I lose a lot fewer doing this vs immediately going in soil.

4) Place cuttings in soil or rooting medium, buried up to just below the intact leaves, covered with a humidity dome and with bright light at least part of the day.

5) Keep it from drying out (but not soggy) until vigorous growth (6+ months). If it wilts or browns, it's dead and should be removed.

I've tried both with and without rooting hormone and haven't noticed much of a difference, both ways I'm around 50% loss rate.

sc4001992

  • Hero Member
  • *****
  • Posts: 3904
    • USA, CA, Fullerton
    • View Profile
Re: Cold Hardy Avocado Rootstock
« Reply #8 on: January 27, 2023, 05:24:34 PM »
Have you tried your method for persimmon, loquat, white sapote, longan or lychee?

drymifolia

  • Hero Member
  • *****
  • Posts: 619
    • Seattle 9a/sunset zone 5
    • View Profile
    • the drymifolia collective
Re: Cold Hardy Avocado Rootstock
« Reply #9 on: January 27, 2023, 05:53:10 PM »
Have you tried your method for persimmon, loquat, white sapote, longan or lychee?

Nope! I think persimmon is extremely difficult to root, not sure about the others.

sc4001992

  • Hero Member
  • *****
  • Posts: 3904
    • USA, CA, Fullerton
    • View Profile
Re: Cold Hardy Avocado Rootstock
« Reply #10 on: January 27, 2023, 06:44:42 PM »
ok, thanks. I have rooted white sapote. Will be trying prsimmon now.

Va Beach Grower

  • Member
  • ***
  • Posts: 39
    • USA, VA, Virginia Beach, 8A
    • View Profile
Re: Cold Hardy Avocado Rootstock
« Reply #11 on: January 27, 2023, 09:02:17 PM »
I could probably write an opus on my attempts to root avocado cuttings. There are also some good old journal articles on this question, where they found that Mexican avocados rooted much more easily than Guatemalan (intermediate success) or West Indian (almost zero success), but it can take many months to root. Based on those studies and my own testing of methods, this is what has worked best:

1) Cut the branch tips right near the end of a flush (done expanding but not done hardening), removing at least 5-6 inches. This works best if the bottom of what you remove has finished hardening (firm stem) even if the new leaves at the tip have not.

2) Trim off all leaves except the smallest 2-3, and remove the dormant buds next to the lower leaves, too (roots only form on callus, not from bud sites, which might rot).

3) (optional) I now store those prepared cuttings in the back of an aquarium filter (filter media removed) until they form nice bumpy callus (a couple weeks). I lose a lot fewer doing this vs immediately going in soil.

4) Place cuttings in soil or rooting medium, buried up to just below the intact leaves, covered with a humidity dome and with bright light at least part of the day.

5) Keep it from drying out (but not soggy) until vigorous growth (6+ months). If it wilts or browns, it's dead and should be removed.

I've tried both with and without rooting hormone and haven't noticed much of a difference, both ways I'm around 50% loss rate.

This is awesome,  thanks so much for the info, I'll take your tips and give it a try!

drymifolia

  • Hero Member
  • *****
  • Posts: 619
    • Seattle 9a/sunset zone 5
    • View Profile
    • the drymifolia collective
Re: Cold Hardy Avocado Rootstock
« Reply #12 on: July 11, 2023, 04:14:49 PM »
This seems like the best thread to share this news -- I reached out to Marc at Fruitwood Nursery to ask if they have any plans to sell seeds or seedlings of the hardier avocado cultivars that they currently only offer as scions, and this is what he said:

Quote
We will grow more varieties of seedlings as soon as our trees produce enough to do so. The types we do sell are generally seeds we can obtain in sufficient quantities from commercial sources.

Best,
Marc

No word on how soon that will happen, but at least it's something they do plan to do in the future. So maybe there will finally be a source of hardy seedlings sooner or later!

pagnr

  • Hero Member
  • *****
  • Posts: 941
    • View Profile
Re: Cold Hardy Avocado Rootstock
« Reply #13 on: July 11, 2023, 04:49:40 PM »
Have you ever tried preparing cuttings while still attached to the tree.
Pre callusing, trimming off the leaves and wounding and taping up.
Allows the process to start before you remove the cutting.
There is also etiolation, excluding light from the stem to induce roots.
I once wrapped citrus branches with Aluminium foil to try to induce flowering. Instead got a few 1cm roots under the foil.

drymifolia

  • Hero Member
  • *****
  • Posts: 619
    • Seattle 9a/sunset zone 5
    • View Profile
    • the drymifolia collective
Re: Cold Hardy Avocado Rootstock
« Reply #14 on: July 11, 2023, 05:04:45 PM »
Have you ever tried preparing cuttings while still attached to the tree.
Pre callusing, trimming off the leaves and wounding and taping up.
Allows the process to start before you remove the cutting.
There is also etiolation, excluding light from the stem to induce roots.
I once wrapped citrus branches with Aluminium foil to try to induce flowering. Instead got a few 1cm roots under the foil.

Etiolation helps from what I've read "in the literature" but haven't tried it because I don't have an easy setup for it. I have not tried preparing the cuttings on the tree ahead of time either.

My rooting efforts are mostly something I do to avoid throwing away branch tips that I'm removing already for some other reason (pruning, grafting, collecting scions, etc), rather than a core part of this project, so I haven't put as much forethought into each one as I probably should. I just trim them and stick them somewhere and then eventually pot them up if they don't die. I've also lost track of the ID for many of my rooted cuttings because of that.




Avofan

  • Member
  • ***
  • Posts: 48
    • Oakland
    • View Profile
Re: Cold Hardy Avocado Rootstock
« Reply #15 on: July 17, 2023, 02:04:43 AM »
You can make clonal rootstock by getting Aravaipa, Duke, Mexicola scions and graft to the whatever seedling. Once it heals well you can bury the graft and it will start making roots above the graft. This will make rootstock that is in theory as resistant as the original Aravaipa tree. I have one Aravaipa grafted to Hass and I’m planning to make several own-root aravaipa but it takes a long time.

drymifolia

  • Hero Member
  • *****
  • Posts: 619
    • Seattle 9a/sunset zone 5
    • View Profile
    • the drymifolia collective
Re: Cold Hardy Avocado Rootstock
« Reply #16 on: July 17, 2023, 09:46:07 AM »
You can make clonal rootstock by getting Aravaipa, Duke, Mexicola scions and graft to the whatever seedling. Once it heals well you can bury the graft and it will start making roots above the graft. This will make rootstock that is in theory as resistant as the original Aravaipa tree. I have one Aravaipa grafted to Hass and I’m planning to make several own-root aravaipa but it takes a long time.

In order to make it truly clonal rootstock, you also need to cut off the "nurse root" (original rootstock) once your buried graft forms its own roots.

I have not had as much success getting buried graft unions to form roots above the graft. Even as much as 1 year later, I've repotted trees with buried grafts and seen no roots above the union.

I'm sure there are tricks to getting that to work, since that's how it's done commercially for clonal rootstocks, but so far at least I've found it easier to just skip the nurse root and root the cuttings directly instead. Even though the success rate is low, at least it's very clear which have succeeded once they start pushing new growth a few months later.