My other concern besides the temps is the wet. How do these do with the endless soggy months? Do they handle it better than citrus? Because citrus I have to plant in a raised bed. I planted one in the flat ground 3 years ago and it turned completely yellow before Christmas. I yanked it up and put it in a pot to recover in the greenhouse and now it’s doing well outside on a berm. I already almost killed those avocados with bad soil this summer and they are just now recovered to where they were in June. I don’t want to drown them now.
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That was what everyone warned me about, but I’ve never seen any problem with the ones in the ground. In pots, yes, they suffer if they aren’t brought under cover to protect the pots from getting waterlogged.
But my soil here never has standing water. I’m on glacial outflow deposits that seem to wick away water once the soil is moist (it is highly hydrophobic when dry). I’ve never seen any sign of winter root stress in avocados in the ground. If your soil has poor drainage, you’ll want to plant on berms or such.
My citrus, even in the greenhouse, all turn very pale in the winter. I think it’s the cold, not water related. The only one that stayed deep green for me in the greenhouse last winter was the suspected yuzu seedling.
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Well the avocados growing in Northern California often get rain storm after rain storm for months and never show any distress. In wet years the amount of days with precipitation in some parts of Northern California can be nearly the same as the Willamette Valley. Particularly avocados growing in the counties north of the golden gate. Santa Rosa is only 45 miles from the bridge’s south tower and gets 50% more rain on average than San Francisco. There’s a town called Cazadero in Sonoma County, just 15 miles north of Santa Rosa, that gets over 60 inches of rain in an average year.
My citrus that turned yellow in the ground was actually a flying dragon, and it had already dropped its leaves. It was the stems and trunk that turned yellow from the clay soil getting water logged. I yanked it out, put it in a pot with well draining soil and it turned bright green by winter’s end.
The only citrus that turn yellow for me are outside, never in the greenhouse. They also tend to drop a significant amount of leaves. That’s why I was asking about what material you use for cold protection. I’m thinking about adding some on nights that drop below 25 to see if that improves performance early in the growing season. They are too big for a bucket.
I figure whatever I use for the citrus is something I can eventually use for the avocados. I had planned to put them in the ground this summer, but the fiasco with the crappy soil set them back too much. So now I’ll aim for next spring.
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Hallo,
I’m new to this forum and I’m fascinated by your experiments and success to grow avocados. After I’ve red about cold hardy varieties this spring, I would love to plant an avocado tree in my garden (I live in the south of Germany).
I would like to use Duke7 as rootstock, but I couldn’t find any source in Europe. I could buy Mexicola seedlings, Topa topa seedlings or a two year old Duke7 with Haas graftet on to it. I could not find information about the cold hardiness of Topa topa. Does anybody know? Which rootstock would you recommend?
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Welcome to the forum!
I don’t know much about EU-based nurseries, maybe @Luisport knows of one that sells Duke7 in Europe?
I have wanted to grow Topa Topa to see how hardy it is, actually, but couldn’t find anyone selling either seedlings or the grafted variety in retail nurseries here in the U.S. It should be fairly hardy, but I haven’t seen any explicit discussion of its hardiness.
One option would be to buy the Hass on Duke7 and plant it outside. The graft will probably die in the winter, but maybe the roots will sprout in spring, and you could graft on those shoots.
Mexicola seedlings grow somewhat more slowly than most other hardy varieties I’ve grown from seed, so they may take a little longer to reach a graftable size, but should work ok as well.
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It is highly soil dependent, I think. Avocados will not like, for example, if they are in this:
My subsoil here is mostly compacted sand, but with a good amount silt/clay, too, and plenty of weathered gravel in the mix as well. It never really gets “waterlogged” no matter how much rain we get, the water seems to drain on through.
If I dig a 2’ deep hole and fill it with water during the wet season, it will vanish in 20 minutes, tops. It takes a little longer in the dry season, actually, since the soil is initially hydrophobic, but once it gets wet it drains very well. If your soil does not similarly drain well, you should definitely plant avocados on a mound.
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Two new additions this year are “Hamada” seedlings from @george, one of which was damaged a bit in transit and slow to regrow, and the other was vigorous but had a failed graft that set it back a little:
I can’t find my notes for them, but my recollection is that is either a sport or seedling of Bacon.
So far only one Bacon seedling has made it through the winter (out of a couple dozen tried), and that one failed to make it through its second winter, so overall Bacon seems insufficiently hardy.
But maybe Hamada is hardier!
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Thank you very much for your information. It’s an interesting idea of planting the grafted Hass on DUke7 and letting Hass die. I was considering cutting below the grafting point and graftig a new variety onto it, but this might not be possible if the grafting point is too close to the roots.
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That may also work, but I’ve found I have much better luck grafting on new growth as soon as it hardens, rather than grafting on an older stem/trunk. Brad Spaugh (an avocado grower active on another forum) also generally advises cutting the rootstock to a stump and then waiting for new growth and grafting on that once it hardens.
If you plant the Hass and it doesn’t die (mild winter), you may still want to stump it early in spring before it starts to bud out, and you should get plenty of good shoots from the roots then. And if you are unsure whether the shoot is from above or below the graft, just crush a leaf. Duke7 should have a strong anise scent, Hass has none.
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Hallo Lea
Herzlich willkommen im Forum
I don"t have much experience with planting out avocados yet, I only have two fuerte seeds that I planted in my garden last year and which I had grafted with lila and poncho this spring.
Fuerte was just the hardiest variety I could find in stores. But I have around 20 plus grafted trees in pots. Some of them are grafted on mexican roltstock, some on fuerte, bacon, wilma and hass. With one I did this spring exactly what swincher suggested. It’s a 20 year old potted avocado tree, probably hass, that never flowered,. I cut it down at soil level and grafted three emerging shoots with lila, poncho and joey.
That was, maybe 5 month ago. Now it became already a very strong tree with lots of side brunches. Around 1m in hight.
The rest are all grafted seedlings from 22 and 23. I also have fantastic, topa topa and mexicola.
Do you live close to the swiss border?
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Here is thae old root dtock wirh three different varieties on it.
Together with the most of my grafted avocados.
@swincher this is the seedling I posted earlier, when I asked you whether you have an idea what it could be. It is still holding the last leaves fron 2021!
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It looks a lot like my Mexicola Grande seedlings. Here’s one (#51) that I’ve had outside since spring 2021, but it has died above ground both winters and regrown again each growing season:
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Yes indeed, it does look very alike.
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Hallo Marcel,
Where do you live? I live in Karlsruhe, but my parents live in Freiburg and my cousin even works in Switzerland.
Your avocado plants are impressive. It’s interesting to see that the tree you grafted five month ago is already that big. I’ll definitely try to cut off/ let die the Hass on the Duke7 and graft on the new shoots. It is really difficult to find rootstocks. I found a nursery in Malaga which sells Duke7, but they don’t ship at all. Another one in Malaga sells the Mexicola, Topa Topa and Duke7 grafted with Hass and ship within Spain. I’m organizing someone in Spain to receive the plants and send them to me to Germany.
Would you maybe sell/ exchange some scionwood at the time I have graftable rootstocks? You have got exactly the varieties I was planning to buy from the USA (Lila, Fantastic, Poncho).
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I agree with this. My understanding is that Northern California avocado growers don’t just plant it in the ground and they do a lot to protect the roots, e.g planting it on a mound, ensuring proper drainage, irrigation setup, etc. If you just took a survey here in Bay Area among backyard growers, almost everyone would have killed an avocado. While our soil is not hard clay, the water retention is enough to kill the young avocado tree planted in the ground without any additional help. Having said that, I am experimenting with just planting the seeds straight into the ground and my hypothesis is that the undisturbed taproot helps with many of these issues and these seedling rootstocks don’t need any additional protection.
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I killed some avocado trees in Sonoma County before I figured out how not to. I think the biggest culprit was cold, though looking back on it now it’s possible too much rain might also have contributed.
It was about 15 years ago and we had endless rain that winter and spring, getting our last soaking, 1.5” on June 29th. Over 40” of rain fell in five months that year. Though the avocados and meyer lemon trees died in February, before most of the rain had fallen, when we had a series of nights with lows in the high teens. I believe 17 was the coldest morning that winter.
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Interesting. I think the epicenter nursery in Santa Cruz also mentioned the same about losing their avocados to the cold. However, all of their trees are already planted on mounds and have proper drainage. Here in San Jose, I don’t think most avocados are killed by cold. They either die due to root issues or not enough irrigation during our dry and hot summer.
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I’ve killed a couple from forgetting to water them in summer, too! Though I finally got a (ridiculously large) chipdrop recently, so that should help a lot with keeping things wet enough for the next dry season.
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That flush ended up very vigorous, almost finished hardening now and about 3’ of growth on the longest branch:
@maesy is this starting to look more like the one you saw when you went to the nursing home, or could it be a different tree somewhere else on the grounds?
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That is hard to say. There was no new flush at the time when I was there.
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