What’s the legality of mailing pollen into the country? Are any diseases carried by pollen? Does Avocado pollen remain viable long enough when dried?
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All parts of the avocado are prohibited other than whole fruit of the Hass cultivar only, and only from commercial growers in specifically authorized countries. Here’s how the USDA/APHIS Plants For Planting manual defines a plant, explicitly listing pollen as an example:
Plants are any plant (including any plant part) for or capable of propagation, including a tree, a tissue culture, a plantlet culture, pollen, a shrub, a vine, a cutting, a graft, a scion, a bud, a bulb, a root and a seed.
As far as the second question, sunblotch viroid (ASBVd) can be transmitted by pollen. Presumably that means other viruses or viroids might be, but that is one that I know for sure. Infected pollen does not cause the viroid to infect the tree that the pollen pollenizes, but it causes the seed inside the fruit that forms to be infected. In other words, if ASBVd-positive pollen is applied to a flower on an ABSVd negative tree, the recipient tree does not get infected, but all seedlings from seeds created by the pollen will be “born” ASBVd-positive.
I don’t know the answer to the viability question, though.
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My husband and I have a Mexicola that we managed to keep alive over last winter in zone 8a. It was a horrible winter, extra long and extra cold. It even snowed in Redding.
I bought a plastic dome to keep it (and citrus) in and when it was 11f we would put a couple of kerosene lanterns in to heat up the dome a bit.
We also have 4 Owari Satsuma mandarin trees (2 semi dwarf rootstock, 2 on own roots), one Palestinian sweet lime, one kumquat, one Rangpur lime, and one morro blood orange.
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Thank you for sharing! How often does it get that cold there? 11°F is going to be a tough temperature for that tree to survive once it gets too large to protect, though you could prune it to fit under a cover of some sort for bad freezes.
Redding is actually one place I’ve been meaning to try to find hardy seedling avocado survivors. Do you happen to know of any trees in the area? I assume there aren’t any that are surviving unprotected up your way, but maybe a little further down in the valley.
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No, though Marta may again at some point. Your best bet would be to just visit Oroville and collect scionwood or seeds directly from the famous tree there. I should be able to share scionwood next year, too.
I don’t have any theories yet. I noticed the leaves don’t really have an anise scent, so it may end up being not very hardy. If you ever are in the area and check on it and see ripe or fully mature fruit on the source tree, that would be a big help with an ID.
Time will tell! Most pure Mexican avocados ripen in 5 to 10 months in southern CA, so any of them are a possibility, but really there’s not much data published for most Mexican varieties, since they have minimal commercial appeal. But it will be a few years yet before I can give a meaningful answer about ripening times either in the greenhouse or outdoors for most of the varieties I’ve collected.
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I do not know anyone else that has an avocado plant near me - however; Wyntour Gardens sells avocado plants - they may have leads on who has them. Maybe even some of the employees might have them.
I applied to get a grant to help get a high tunnel, in which case I will put the avocado in the ground inside the high tunnel, if I am accepted and can afford it.
Shasta county wants $2000 for a permit for a greenhouse - seems a little crazy just to grow some vegetables. A high tunnel is not even a permanent structure.
Good ol’ California, always bending its citizens over…
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I potted up some more germinating seeds last night, this time the seeds of a suspected “Joey” tree in Gainesville, FL. Out of the ~23 seeds, four of them showed a kind of rot I’ve only ever seen in seeds from FL, so I assume it is a pathogen they have there. Never seen anything like this in seeds I germinate from California or anywhere else:
I threw out the three that seemed affected, hopefully it doesn’t spread. Here’s what the healthy ones looked like:
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Noticed something interesting today, the two seedlings of “Hamada” (from @george) seem to be very, very different levels of hardiness.
The one that took the cold the worst was planted in the ground upon arrival early this summer, and then became sunburned and drought-stressed, but recovered a bit in early fall. It has basically already been killed back to ground level (again, after sunburn did that first):
The one that was in a pot in an even more exposed location (but was protected from the sun this summer) shows no frost damage whatsoever:
That is pretty impressive for a SoCal “Bacon-type” (likely seedling or bud sport)! By comparison, this is a normal Bacon seedling that was in a pot right next to that one for the same freeze:
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I’m curious what constitutes hardiness for the avocados you’re rating. Is it also determined by the ability to withstand a climate that only warms into the high 30’s and 40’s during the day, after freezing at night? Or is that irrelevant?
When I lived in Rincon Valley for about a decade there were a few very cold spells that burned the leaves of that mother tree. The worst was a night down to 17. The entire top of the tree was crispy, though it bounced back within a couple of months.
Do you think it matters for the health of the tree that even after the coldest nights in Sonoma County the temps usually climb back into the 50’s? Days when high temps remain in the 40’s are fairly rare, happening maybe ten times in an average winter. It’s when the Tule fog settles into valley, after heavy rain, that the daytime high temps remain frigid.
I was also wondering about the anise scent, because I swear I can smell it ever so faintly. A couple of other people I’ve asked agree, while one guy didn’t. Do some hybrids end up with a faint anise scent sometimes?
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The way I usually describe the goal of this project is to find avocados adapted to our climate here in the Cascadian lowlands. So that would mean adapted to all aspects of our climate, able to survive both our coldest lows and the general pattern of winter weather in the region, which includes cool highs and regular mild freezes with just occasional “test” freezes.
I’m sure that for some trees, the overall cool pattern will be just as damaging as the cold snaps. Last winter, one of the trees that survived the worst freeze (17°F) was much more damaged two months later by 25°F after it had begun to bud out earlier than any of the other trees. So “staying dormant until last hard frost” is something to select for as well.
I’m sure it’s a trait like any other, which could be passed along to some hybridized offspring to varying degrees. However, most of the cultivars usually considered Mexican hybrids (Bacon, Zutano, Fuerte, etc) have little to no scent, while most pure Mexican cultivars have a fairly strong scent. Del Rio is an exception, with only a faint scent despite clearly being Mexican in most other ways.
I’ve noticed that some seedlings of Royal-Wright (which seems like a hybrid and has no scent) have a fairly strong scent, and I usually suspect those were crossed with Duke (the only other pollen source nearby according to Marta), and their leaves often resemble Duke more so than their seed parent. So complex Mexican-dominant hybrids may have the scent even with some Guatemalan genes in the mix.
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Would that be Rincon Valley as in Santa Rosa, California?
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Yes, @jsteph00921 collected scionwood from a tree there and it’s one that is in the collection for this project now.
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I have purchased a few avocados plants and all have died, except for one Mexicola.
When doing avocado research, I read that the Mexicola variety has edible leaves and they smell like anise and in parts of Mexico they put the leaves in their bean pot to flavor the beans.
When I crush the dried leaves of the Mexico tree, it has a very strong anise smell.
The Mexico is supposed to have smaller fruits with a bigger pit, but very high-quality flesh. It’s also supposed to be one of the more cold hardy varieties.
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All avocados of the Mexican botanical group (“race”) are used that way in Mexico. I’ve found Duke and Linh have even better flavor than Mexicola.
I’ve mostly seen Mexicola fruit with smaller pits, but yes the fruit is very small and the flesh is quite tasty. Marta posted photos up in this thread of her Mexicola fruit next to a Duke fruit:
As far as cold hardiness, Duke and Aravaipa seem hardier than Mexicola for me so far, both in terms of grafts and the hardiness they pass along to their seedlings. The little-known cultivar “Northrop” aka “Northrup” was recommended to me as one of the hardiest cultivars by the post-doc who manages the UC research grove, and it has done well in its first year for me so far as well.
Here are a couple photos of Northrup last winter, the second one shows how much damage it had as a result of 17°F, protected only by placing a large lawn chair on the north side, leaning over it somewhat, and the completely brown branch on the lower left belongs to the rootstock, which is clearly less hardy:
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Someone gave me some tiny avocado seeds that I planted and now have three small seedlings. Is it only the Mexicola that have those little ‘Barbie’ pits or do others have them as well? I have no idea what kind of avocado these seeds came from.
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An 8a is really cold. Have you considered an unheated greenhouse? I’ve not yet gotten fruit from my avocados planted in the greenhouse, but they are super happy and bloom like crazy. And the meyer lemon trees in the Pringle Creek greenhouse yield around 100 fruits each winter. I expect the satsumas will produce some nice fruit next year. No clue if they’ll be sweet. The meyer lemons we get are fairly sweet, but not nearly as sweet as the meyers growing in California, which are nearly as sweet as oranges. I have no idea what the avocados will taste like since I’ve yet to figure out what the heck they are.
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I haven’t quite figured out the “why” of it, but even Hass sometimes form tiny fruit with tiny seeds. During the sorting/grading process those usually get discarded because they are below the threshold for “small” Hass, but they’ve recently been marketed as “teeny tiny” or “single serving” avocados. I actually have a few of them I’m growing because I was curious if they even had viable seeds (they do). Here’s where I posted about them up-thread:
And here’s how Trader Joe’s describes them:
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the plants you gave me and my two own trees are still holding strong in the greenhouse- it has been 40F at the lowest in there at nights, gets only up to about 55F in the day and there’s a little supplemental light for an extra hour after dusk. they are continuing to grow at this level. next year one of them and one of mine will go in the ground outside with heavy winter protection and some xmas lights for warmth; I’m 6b (or 7a) so it’s a real reach, but I will test the protection. I’m half done building a black fruit wall from ecobricks, south facing, so that should also help.
gosh those leaves are filthy. I’ll have to scrub up a little tomorrow.
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Thank you for the update! I’d love to see if it’s possible to protect them in your climate. I’m guessing the answer will be no, but I’d love to be wrong, and it sounds like you’re going to do all the things that could make it possible at least. The biggest issue will be if the ground around it (within dripline) freezes solid. Avocado roots die completely when that happens, I have been told.
Usually a sign of scale insects or something else that sucks sap and produces “nectar”… My Jade tree is for some reason extra prone to scale insects and its leaves are almost black sometimes! I don’t spray anything, but I’ve been told hort oil will help, or of course insecticide. I just use soapy water and elbow grease. Lots of the latter. The tree doesn’t look like it suffers too much from either the loss of sap or loss of photosynthesis, though.
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Hi, here comes the update about the Avocado.
I visited the site today and found the tree even more magnificient than i thought. It´s huge! Leaves with anis scent and he looks fine with the already low temperatures. Most likely dormant now for the winter.
Several fruits on the tree. Smaller, violett peel and tasty 
I am adding here pics from tree, leaves and ofc the avos.
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