Florida Fruit Geek

For the last two decades, I’ve been propagating and planting some of the most cold hardy types of avocado, pure Mexican subspecies varieties like ‘Del Rio’, ‘Gainesville’, ‘Mexicola’, ‘Opal’/’Lila’, ‘Wilma’/’Brazos Belle’, ‘Joey’, ‘May’, and ‘Poncho’, as well as seedlings that are crosses of the above varieties.

These pure Mexican subspecies (Persea americana drymifolia) cultivars can generally handle brief temperature drops to at least the upper teens F (-7C) as mature trees with little or no damage. The trees do well here in North Florida, supplying us with home grown avocado fruits from June or July into the middle of October most years.

It’s now been well over a decade in which winters that have not dropped below 20F at my location, and in some winters temps didn’t even drop below 32F. I’m getting curious about pushing beyond the pure Mexican varieties, expanding into cultivars that aren’t quite as cold hardy. Pure West Indies varieties, which thrive in heat and humidity and do well in South Florida, are probably still too sensitive for this area. They’re typically hardy to about 28 to 30F, which means they would likely be subject to freeze damage most winters here unless covered during the cold snap. And pure Guatemalan types reportedly don’t like Florida’s sauna-like weather (I’ve heard mixed reports on this).

But there are a number of varieties which are mixes of genes from two or even all three of the avocado subspecies, and are intermediate in their cold tolerance. Many of these cultivars have much larger fruits than pure Mexican types, with a harder skin that makes them more resistant to the surface imperfections common in pure Mexican variety fruits grown here. And many of these varieties ripen later into the fall and winter, potentially extending the avocado season in this area.

I figure that anything which can handle temperatures down to the mid 20s F should be able to handle many winters here without extra protection if located near evergreen trees. By pruning the trees to keep them small, I’ll be able to cover the whole plant during the occasional freeze that drops below the mid 20s F.

By grafting these medium-hardiness types onto seedlings of pure Mexican varieties like ‘Del Rio’, I can make sure the rootstock is even more cold hardy than the scion, so there won’t be an issue of a cold hardy grafted tree getting its cold sensitive rootstock killed out from underneath it, thus dooming the whole tree. Possibly the rootstock could even impart a tiny bit of extra cold hardiness to the scion.

As these medium cold hardiness varieties come into bearing, surrounded by extremely cold hardy, pure Mexican subspecies trees, the different types should cross pollinate, and their seedlings will contain interesting mixes of genes from the different subspecies.

So I am acquiring avocado varieties that are reported to handle temperatures down to at least 25F, which are known to do well under Florida conditions (steamy hot rainy summers), and of course, cultivars with good flavor and productivity. Following is a list of the ones I’ve acquired so far. I’d be interested if anyone has any other suggestions, please leave a comment or contact me.

Brogden

This is a well known avocado in Central and South Florida. I’ve seen it sometimes listed as a mix of Mexican and West Indies, and sometimes as a “complex hybrid”, possibly containing genes from all three subspecies. I’ve actually had this variety for a number of years – I planted out an air layered specimen in my grove in Citra around 2006. I located that tree in a fairly shady spot for cold protection, probably too shady, because the tree grew very slowly. The winters of 2009 to 2011 dipped repeatedly into the teens, so frigid that even in the sheltered spot, the tree got knocked back. It regrew (advantage of an own-root tree), and fruited from 2019 to 2022, with excellent flavored avocados, much larger than any of the pure Mexican types.

Unfortunately that original tree succumbed to Laurel Wilt disease in spring 2023. (A large limb had snapped off in a wind storm, leaving an open splintering wound – I think that’s where the disease-carrying beetles made their entry.)

I also have a younger Brogden tree planted around 2020 or 2021, located in a more exposed, sunny location than the original tree. It grew much faster, and had reached about 12 feet tall by late 2022. During the Christmas 2022 freeze (23F, -5C), I wrapped a sheet of ground cloth around the tree as high as I could reach. It’s fortunate I did that, because all the uncovered foliage and branches above that point got killed by the freeze, and everything covered by just that single layer of plastic came through undamaged. I didn’t put any sort of heat source under the cover.

That result shows how a very minimal cover can sometimes make a huge difference during a freeze. Partly based on that experience, I plan to regularly prune any of the less cold hardy avocado varieties to keep them smaller and easy to cover during freezes.

I think my younger ‘Brogden’ tree could have its first fruiting in 2024, and I am propagating more trees of this variety to plant out in the grove and for sale.

‘Oro Negro’

I keep hearing rave reviews of the flavor of ‘Oro Negro’ avocado. It’s relatively new in the nursery trade, possibly a cross between ‘Monroe’ and a Mexican variety, reportedly hardy to mid 20s F. The name means “Black Gold’ in Spanish (this is a black-skinned variety).

I ordered a plant from Lara Farms in Miami in spring 2023. The plant they shipped was an excellent specimen – it already had some branches, enough to immediately supply a few pieces of scion wood. Since that farm is in south Florida, the rootstock is unlikely to be an extremely cold hardy type, so I don’t want to risk that plant in the ground.

I immediately snipped off a few of the branches and used them as scions to graft onto one of my pure Mexican seedlings. One of the grafts took well, pushing growth just three weeks later. The other grafts look promising, so I should soon have trees to plant out in the grove.

‘Lula’

‘Lula’ (not to be confused with ‘Lila’, a pure Mexican variety) has been grown commercially in Central and South Florida since the early 20th century. Reportedly its parentage is West Indies mixed with Guatemalan, hardy to about 25F. I’ve eaten ‘Lula’ fruits at the Fruit and Spice Park in Homestead, and I thought they were excellent.

This is another plant I ordered from Lara Farms in spring 2023, and again they sent me a nice, husky plant, with enough branches for a couple of pieces of scion wood. At least one of the resulting grafts I did onto pure Mexican seedlings looks promising already.

‘Bacon’

Another variety that’s reportedly hardy to mid 20s F. I’ve never tasted the fruits of this one. Some reports say it’s good flavored, others say it’s bland. (The name is after a person’s last name, not out of resemblance to the taste of bacon.) I have one small plant of ‘Bacon’ avocado in the ground, and plan to propagate at least a few more (I’ll wait till I get to taste how the fruit quality is before deciding to propagate in quantity).

‘Tyner’

This is a local seedling variety from Gainesville. Its parentage is uncertain, but definitely seems to have Mexican parentage, along with possibly some West Indies genes. The parent tree suffered some winter damage during the 2022 Christmas freeze, but still managed to flower and set fruit after that.

Fruit quality of ‘Tyner’ is excellent, quite similar to ‘Hass’. I’ll have more to say about this variety in a profile post.

‘NSB1’

This is another uncertain one. The parent tree is in New Smyrna Beach, hence the name. Reportedly it was purchased from a nursery, possibly as a ‘Florida Hass’. I think I’ve heard different cultivars called ‘Florida Hass’, and this might be the same as one of them. Until I can confirm that it is the same as an existing cultivar name, I’m just calling it by the code name ‘NSB1’.

Eating quality is delicious, and fruits are much larger than any pure Mexican variety, so it probably has West Indies genes. Bumpy skin indicates it also likely has some Guatemalan parentage. Exact hardiness is unknown, but New Smyrna Beach does sometimes get temperatures into the 20s F, so the variety should have at least some ability to tolerate sub-freezing temperatures.

I acquired scions of this one in early 2023, and I grafted them onto cold hardy seedlings of pure Mexican varieties. I’ll be planting these out in the grove either later this year or early in 2024.

Other varieties I’ve heard recommended for central Florida are ‘Choquette’, ‘Day’, ‘Hall’, ‘Monroe’, ‘Nishikawa’, ‘Simmonds’, and ‘Super Hass’/’U La La’. I’d be interested if anyone has information to report on growing any of these in Central or North Florida. If you can supply material, especially if you want to trade scions, please get in touch.

***Note: The mention of Lara Farms in this post is uncompensated. I ordered the plants from their website, and I paid the price listed. The plants they shipped were large and healthy. I like to give a shout out to business that are doing a good job.