As long as the ground doesn’t freeze solid, conventional wisdom seems to be that rootstock hardiness doesn’t matter too much, especially if you plant with the graft union below ground (or more accurately, with soil mounded above it).
Florida and south Texas nurseries tend to use Lula seedlings for all grafted avocados because they are readily available in the trade, tend to be vigorous, and can handle their local alkaline or higher salinity soils better than hardy types. Of course salinity and alkalinity aren’t really concerns for the PNW other than maybe some low-lying coastal stretches.
Just realized I should probably update this thread with a recap of the results of the late December killing freeze (6 days of freezing temperatures starting with a low of 18°F and ending with a low of 15°F).
I’ve posted a tweet thread with photos and specific details about particular trees, but the gist seems to be that all the in-ground trees survived below the snow line, a few of them survived to varying degrees above the snow line, and even a few of the potted seedlings appear to have survived. Here’s a grafted Joey tree that looks mostly alive despite defoliating:
@Luisport may be able to recommend some to you, or if you check through this thread you may find some options.
It is not possible for any US members to send you materials unfortunately. Welcome to the forum!
Hi! Here you have several hardy varieties: I advice you ettinger, bacon and fuerte. On fruit quality ettinger is really good. Regarding hardiness bacon and ettinger on my location are the best ones.
Ettinger, Duke7, and Fuerte are all Mexican types, and out of those Duke7 is probably the hardiest. Bacon is a relatively hardy Guatemalan type that is sometimes mischaracterized as a Mexican hybrid.
And as for the cultivars not readily available in the E.U., obtaining phytosanitary certificates seems like a bit of a challenge for avocado cuttings or seeds, so I’m not willing to send them internationally myself.
I don’t know what variety it was, but when I was a kid in Palm Springs we rented a house with a 30’ tall avocado tree. They looked and tasted like haas but I have no idea if they were. There were lots of big grapefruit and orange trees growing with it. Plus a couple date palms. That tree has no problem with the many days above 110 degrees and more than a few morning that dropped below freezing. We even had 2-3” of snow accumulation in 1978 and 1985. Neither time was the tree burned at all.
I don’t think the fruit will require any more summer heat than we have here to ripen, but late winter hard frosts would likely kill flower buds in many years, unless the outdoor trees just flower later here than they do further south.
My trees in the greenhouse (latest photos) seem to be flowering around the same time as those cultivars in California’s central valley. We’ll have to wait at least another year to find out if that holds true for the outside trees.
What temperature do you keep the greenhouse? Last year I was keeping it in the 50’s but that got pricey since I use electric heat. So this year I keep it around 40 degrees and everything seems to be fine so far.
Right now the two heaters each are set to turn on around 50°F and usually turn off around 55°, so usually the greenhouse spends the night with temperatures doing a saw pattern, like this (sometimes the two heaters sync well and sometimes less so):
But it got down to 42° when it was 15° outside in late December. I’ll probably lower the threshold temperature next year, but I do have a couple truly tropical things in there that look sad even with these temperatures, and might need to become winter houseplants for the warmth rather than greenhouse plants.
Curious what type of heaters you use? I recently ran some 220 out to the greenhouse so I can power a 3600 W bio green electric heater. I’d also like to maybe add a couple drums of water. Though it’s so packed with plants in there already I’ll have to sacrifice something to make room.
My goal is to replicate as closely as I can the climate in Petaluma. The Sonoma county climate might be the best for growing things in the entire country. I never would have left if not for the expensive real estate. I had a condo which was miserable for somebody like me who loves to garden. Yet the median price of a house with a lot down there is 1.2 million. And that gets you a dump at best. Yet it would be a dump where you can grow lemons and avocados. Hahaha. I decided the shift to a zone 8 was worth it to get some land and a nice house for half the value of the condo I sold. It really was a no brainer for me. I figured the trade off would be getting a nice greenhouse to recreate the Sonoma County climate over 50 square feet of my yard.
I’m really interested in your avocado experiments. Do you have any videos posted to YouTube or some other site? Since I was able to grow Mexicola so well in Sonoma County I want to maybe get some sort of a ‘super’ dwarf version to plant in the ground inside my greenhouse. Does such a thing exist? I’m also open to other varieties as long as they work well in a greenhouse. Or is it better to keep them in a pot so they can spend summer outside? I have a 10 foot ceiling in the greenhouse so maybe that’s enough for an in ground avocado. What do you think my options are?
Bonus points if you tell me I can grow fuerte or a Gwen. I grew up in an agricultural tract in SoCal back in the 80’s and we used to feast on those two varieties. The orchards are condos now so I’d love to grow those types in honor of the hours I spent wandering avocado orchard as a kid. Hahaha… Boy is it true that youth is wasted on the young. Took that for granted big time.
Thanks in advance for any assistance you might be able to offer. Is it possible to buy avocado scions/root stock from you? Are you interested in trading for any seeds or citrus plants? I have an extensive seed catalogue from my years of gardening. And I’d be happy to get you a sudachi yuzu. Though I am concerned about the lack of cold drainage at your property. I’m on a hill so we rarely drop below 25 on the coldest night. That cold snap when you got down to 15 we got down to 18. I still think you can successfully grow yuzu outdoors at your location, especially with the excellent drainage (something I definitely don’t have and must create raised beds for anything drainage finicky).
So let me know. I go up to visit a friend in Bellingham at least once in the summer to stay on Lummi island. I’ll probably be going late May this year and could arrange to meet you for a trade on the way up. Let me know. Happy Sunday!
I have two of the “Dr. Heater” electric heaters, 1.5kW apiece. I didn’t want to fork over the cost to run 220 to the greenhouse.
I don’t do videos, but I do post more regular updates to my twitter account that I created just for this project, which is linked above in the thread but here it is again so you don’t have to search for it:
As far as greenhouse growing, my understanding is most avocados can be pruned to as little as 8’ tall and still produce a good amount of fruit, so with 10’ ceilings that should be no problem. If your greenhouse never gets below freezing, you should be fine growing any avocado cultivar you want.
I’d be happy to share or trade scions and/or seedlings, though if you’re only planning to grow them in the greenhouse then you probably would want more traditional cultivars (Gwen, Fuerte, etc), which I don’t have but are readily available in the trade. If you’re willing to plant a few trees outside then I’d be happy to share my hardiest rootstocks grafted with my hardiest cultivars!
So I would have success growing the hardy cultivars outside? Would I have to do a set up like I have for my meyer lemon? Or could I just grow them like I do the yuzu? Just in a raised bed in front of a 20 foot south facing wall, without wrapping. And why isn’t it possible to plant one of the hardy avocados in the greenhouse? That is perplexing. I don’t have twitter, but I probably should get it for this information.
