I agree there are definitely unsubstantiated claims floating around when it come to plant hardiness. Though I don’t think high teens is a stretch for some of these Mexican cultivars.
I lived in Santa Rosa in 2013, during Sonoma County’s last significant cold snap. My weather station recorded 17 degrees for several hours on the coldest morning. All the avocado trees I visited survived, some having almost no damage at all. The worst looking was the Rincon Valley tree which had all of its outer, topmost, leaves burned. Fortunately there was no damage to any woody parts of the trees. So at least in Sonoma County we can safely say those mature avocado trees are hardy to around 17 degrees.
Of course that doesn’t mean we can make a blanket statement, claiming they would necessarily perform with the same vigor and resilience everywhere. Obviously there are several variables that play into a plant’s ability to endure cold.
Forgot to ask if you or anybody else is familiar with an avocado tree I have called Argui 1?
A nurseryman in Louisiana sold it to me. I have only found a couple sources online. The link below in Table 1 claims it is from the Canary Islands where avocados are not native.
I’m not familiar with it, but avocados are grown widely in areas outside Mexico & Guatemala (the only places they are native). That table says that is the WI race (which is misnamed because it’s from lowland Mexico, not the West Indies, though it is widely planted in the Caribbean). WI avocados are usually extremely frost tender, but it’s always possible there could be an exception.
Did some grafting in the greenhouse last night, will probably do a few more today. Thank you @george for the scionwood!
The two new varieties are what he calls “Nancy” and “Derek,” both of which are somewhat similar to Bacon, but do not appear to be identical to each other or to Bacon itself.
The backstory of Nancy is it was grafted many decades ago using scionwood collected from a good quality tree in the oldest commercial avocado grove in California, at the Huntington. The leaves and wood have a clear Mexican/anise scent, but not a strong one.
Derek is a tree that is of unknown history, growing in a SoCal backyard, but suspected to be seed-grown I believe. It seems very similar to Bacon, but the two fruit @george sent are at least twice the size of any Bacon avocado I’ve seen before. I don’t know how big Bacon can get, but I don’t think quite this big?
I did a few grafts of each on one year-old seedlings that had shown too much frost sensitivity over the last month or two, including a graft of each of them on #276, a Fuerte seedling that had a failed summer graft and had produced two graftable stems after that:
Winn, how do you want us to report data? Wait till spring, or just monthly PM updates? I will run out later and check the ID # tag.
The avocado you gave me has not died back yet this winter. The tender new shoots froze off and dropped away first frost, but none of the old foliage was affected. It has since started some new buds at a lot of the leaf nodes. I have left it out in my driveway in a grow bag slightly counter sank into ground about a third of the way. South side of my lot in my most sunny area. Sans any top protection.
I have noticed your trial avocado has very green colored buds/ shoots, in contrast to the very red looking new shoots on my winter volunteer avocado my son found. Neither seems to bothered by the cold so far. Holding strong. I wish ours was not from a Costco haas, it seems to also be very cold hardy.
Good question! There is an update form that members can use to post updates about trees they’ve been assigned. I forget whether you’ve signed up on the website, but once you do that, and once I “assign” a tree ID# to you, you’ll be able to just click the button for the tree on that first page. If you don’t want to sign up there (which is understandable!) you can also just share photos and an update here in this thread, and I’ll post the updates to the database myself.
I guess that Bacon can get that big! The UCR Variety List says average fruit size is up to 18 oz (510 g), so 535 g isn’t wildly outside that range. I think there’s a good chance Derek is Bacon, or at least a seedling thereof that’s pretty close to its parent.
all the trees you sent with me are still putting on new leaves at 40F in the greenhouse. it doesn’t get above 50 in there even on a warm day, there’s just not enough sun here in winter. so they’re active growing at that low temp.
It seems to vary a bit from tree to tree. Some go very dormant early in fall and stay that way until well in the spring, even in my slightly warmer greenhouse, but others continue (more slowly) flushing new growth, and then flowers (on the grafts) by the end of the winter.
For your grafted trees @resonanteye, keep an eye out for flower buds, they look kind of cabbage-y at first and then start to expand. Different varieties look slightly different at this stage, but here’s Duke in my greenhouse now:
If you have flower buds that start opening in spring, I can mail you a packet of fresh pollen if I have anything else flowering at the same time as you!
As a sort of test of the long-term storage capabilities of avocado seeds, the avocado project received a donation of seeds that had been harvested in August 2022 and kept refrigerated for over a year. More than half of those seeds have already sprouted this winter, more quickly than the seeds from the exact same tree that were harvested this year. Here are a couple of the year-in-storage seedlings (the links go to their project profile pages):
My son got a printer for Christmas. Guess what the first thing he printed was? An avocado boat for sprouting seeds in our aquarium. Made me laugh. Silly kid.
Someone posted some printed tags in an old thread. I love that idea and told my son that is what I rally want printed. He said he can do all the tags I need.
The latest GFS run has gone even colder for even longer. Here are the overnight lows shown in the sounding for my GPS coordinates in the 12z GFS (which just finished running), and the highs on some of these days are below 20°F even:
Date
Low (°F)
Jan 12
16
Jan 13
12
Jan 14
7
Jan 15
9
Jan 16
10
Jan 17
15
Jan 18
13
And it doesn’t even end then, it shows that cold pattern lingering basically until the end of the forecast range in late January.
Yikes! Here’s the map for the worst morning (14th), which shows the potential for cold records way down in CA and beyond:
This looks serious and if I were you I would protect as much as you can. I have been following your efforts for years, and it would be too big a loss without any useful selection if you would lose most of your trees now. So I would not hesitate to take all measures to protect them somewhat - they will still have a hard time getting through such a cold period.
I am in Europe, on the other side of the Atlantic, and I have a lot of the same trees you have - avocado’s, Guabiju, Psidiums, Feijoa, cold hardy citrus etc.
Three years ago and last year we had a similar forecast. The first time I protected everything and still had a large number of losses (which is in a way a useful selection) but last year the cold arrived already in November and was initially announced as very mild. But it developed into a strong and long lasting cold and I just lost almost everything that was outside. Not very helpful for making selections when you lose 100% of your most promising trees.
Now I have become a bit more deliberate about the level of cold I want to expose my trees to…
You probably cannot protect everything, but I would try to save the most promising ones…
Ok not that crazy! I have some extra panels from building our greenhouse and I’m just bolting them together to make a box for it. The panels are 8’ long and the tree is 8’ tall, so it works well.
But of course, to punish me for the expenditure of energy (and $), the latest GFS says GOTCHA! and keeps the cold air to the north and east. Here are the last 9 model runs all showing the morning of the 14th, you can see how much it’s been jumping between very cold and very mild here:
So far this latest one is an outlier, but I’m hoping I wasted time and energy and money and we get no freeze at all!
The weather is so unpredictable I was reading your crisis yesterday evening and my weather station said a low of 43 for the night but while I was reading it dropped to 32 so I wasted my time bagging the papaya and avocados only to wake up to 44 and rising. Hard to trust weather predictions when 10 degrees off mean a huge deal to people like us. Hope you can avoid that catastrophic low
