I don’t believe they exist, but does anyone know of work being done to create a super cold hardy avocado that does not have to be brought in doors? This would be my greatest dream realized if I could grow this where I live. I know it’s a long shot, just wondering if anyone heard?
1 Like
You would want to follow the work Winn is doing and that project is no longer being updated on this website.
3 Likes
Nothing remotely possible to survive zone 5, sorry but you can dream. I’d say the coldest zone to possibly keep an avocado (Mexican variety) alive outside would be zone 7b.
7 Likes
Hey, and welcome to the forum!
There are a few projects, yes, but they’re trying to breed for hardiness in zone 8–and even that’s proving to be a tough, lofty goal.
Theoretically, you could do some hybridizations to get even more cold hardiness. The most hardy members of the avocado genus, though not ones that are known to be able to hybridize with avocado and that aren’t even graft compatible with it, are the two species of redbay. Both are native to my area, and both hardy, in the very best case scenario and in protected sites, to no lower than warm 6b, but more realistically 7b.
Zone 5 edible citrus is theoretically, though not practically, possible. But not avocado. Zone 8 hardy avocado is in the works and might happen, but it’s proving really hard and will take a really, really long time. Zone 7 hardy avocado is a pipe dream and probably impossible. Zone 6 hardy avocado is definitely impossible. Zone 5, 5a? no.
But nothing’s impossible indoors given a sufficiently large greenhouse and budget.
5 Likes
@barkrunner welcome to the forum, it’s nice to see another Michigander join. @noogy and I along with a few others are here in W. Mich. @Drew51 , @Chills , @Ribs1 are regular contributors from the East side.
Tons of great people, information , and resources on this forum.
4 Likes
Thank you. I appreciate the welcome. And look forward to exchanging information or even trading with all of you when possible. I am in Northern MI.
Thank you. As it stands right now, it does not appear there are any thing close to my growing zone in development.
1 Like
Not only is there nothing in development there is no visible path to ever get there. There is plenty of things you can grow outdoors in Z5, avocados aren’t one of them
5 Likes
With a walipini greenhouse or other protective measures anything could be grown there. It just depends on how hard you want to try. I would definitely say there are better options available.
2 Likes
Yeah the key word is outdoors
3 Likes
I’m here near Ann Arbor. I love to trade both fruit and knowledge. Let me know if you want to tour my orchard sometime.
2 Likes
Avocados won’t make it in 8B/9A let alone 5A.
The only way they’ll survive 8B is if that 8B is in Florida or Texas where the duration of the deep freeze is a few hours each year. And it bounces back to 50-60 during the day consistently.
Zone only tells part of the story. Duration of cold also matters.
4 Likes
Let’s begin with the facts of Avocados grown outdoors year-round in southern California USDA zones 9 to 11.
They flower sometime between February and April. The ripening period here is 12 to 18 months, depending on cultivar.
So notice that the problem with growing Avocado in more northern latitudes is not cold hardiness, but rather days to fruit maturity. The same is true of most citrus fruits.
If you want Avocado or large Citrus fruits to ripen outdoors in 7 to 9 months, you’ll need to farm in the tropic zone – e.g. lower altitudes of Costa Rica.
1 Like
People like @Marta and Winn (swincher) have shown that Mexican race avocados ripen fruits in 7-10 months even in relatively cool places like the PNW
Guatemalan race avocados are the ones that take over a year to ripen
3 Likes
Pretty much any citrus will ripen to perfection in zone 9a PNW.
It may take 2-3 years but fruit will need protection. As will the tree. It will take a lot of work.
Here he talks about a particular Orange but in personal conversation told me that any citrus will work.
Not sure about avocados.
2 Likes
Winn has not ripened Avocados on trees in his location. Instead, he has seedlings that survived the winter.
Marta’s location is temperate. There are people in the area with 40 year old avocado trees, e.g. Stewart.
The OP has sustained daytime temperatures below freezing during the winter. Also, the growing season is very short compared to yours. A robust greenhouse will be required. This is a far stretch from year-round outdoor growing.
3 Likes
Oh yeah, 5 is a long way from 8B. Even zone 8 requires a LOT of work for citrus.
My point was actually that while citrus is kind of possible in 8-9, avocados are entirely out of reach.
2 Likes
Wait you know Bob personally? I always wondered what happened to him that he doesnt post anything on his channel? I wish he would share more videos.
2 Likes
I spoke to him last year. Not recently.
1 Like
Cold-Hardy Lauraceae Relatives in Zone 5b
-
Sassafras (Sassafras albidum) – Native to North America, sassafras is cold-hardy down to Zone 4. It’s a deciduous tree with aromatic leaves and roots, traditionally used in teas and medicines.
-
Spicebush (Lindera benzoin) – A shrub native to eastern North America, spicebush is cold-hardy to Zone 4 and produces small red berries. The leaves and twigs have a fragrant, spicy scent.
-
Japanese Spicebush (Lindera obtusiloba) – Similar to North American spicebush, it is cold-hardy to Zone 5 and produces yellow flowers in early spring.
Breeding Potential with Avocado:
- Most Likely Candidate: Sassafras (Sassafras albidum)
-
While it’s in the Lauraceae family, sassafras is genetically distant from avocado, making hybridization extremely difficult.
-
However, its extreme cold-hardiness might provide genetic insights into cold adaptation.
-
Any crossbreeding would likely require advanced biotechnology (e.g., embryo rescue, genetic modification).
-
Lindera Species (Spicebushes) as a Secondary Candidate
- While more closely related to avocados than sassafras, they still belong to a different genus.
- No known successful crosses exist between Lindera and Persea species.
Alternative Approach:
Since no Lauraceae species in Zone 5b are naturally cross-compatible with avocado, the best option for breeding cold-hardy avocados would be selecting and backcrossing the cold-hardiest Persea americana** seedlings, especially from *Del Rio,’ ‘Joey,’ or ‘Mexicola’ avocados (which already show some cold tolerance). Another option is looking at Persea borbonia (Red Bay), which is more cold-hardy than avocado but still struggles in Zone 5.
2 Likes