I have seen the one in downtown Charleston. The owner told me it was Gainesville. It reaches to the top of an old two story home. It is somewhat protected by the house, but is otherwise exposed to the weather. I believe the owner told me it was there during the January, 1985 freeze, when, according to records, the area reached 10 degrees F... He had seed when I visited him. I have a clone of the tree, which has never suffered any cold damage despite being left exposed. Mine went through last winter in a pot, without protection. The low here reached 22 degrees and it was otherwise a difficult winter. I believe this avocado compares to Satsuma mandarin in hardiness.

I have been able to root some under mist, with difficulty. I have also budded some; with limited success (maybe 50% takes). I am not sure how they will do on their own roots, but I plan to plant mine (a rooted cutting) this year. I have tried several other hardy types, but none have compared to Gainesville. I believe Eyechecker has one I grafted (or rooted) some years back.

Finally, there are some old interesting papers on the internet on the subject of rooting avocados that can easily be accessed with a search.

Ned

I have Mrs Holland and it went thru last winter here --3 cold spells down near 20--without protection or any damage. I got 4 avocados off the tree this yr--they are relatively small but taste OK to me. I grafted (t-budded) it to a seedling--the tree is only 4 yrs old from seed--about 10 ft tall.

The cold hardy avocados have cold tolerance similar to satsuma mandarin, but they are much more vigorous. Down here in deep south Florida there are commercial avocado groves about 1000 feet from my property.

Beware of the laurel wilt problem if you plant avocado!


I plan to plant avocado, star fruit, mango,lychee ,banana,longans, and passion fruit.


I would love to plant citrus but the citrus greening disease epidemic is a big problem here. They used to grow every variety of citrus here years ago, but not anymore. I have not seen even one citrus tree in any yard or property since I have been here!


I bought some star fruit at Wallmart last week and the flavor is similar to Kiwi in my opinion. Not all that sweet, but good flavor.

I have a Simmonds Avocado which is West Indian type. This variety is NOT cold tolerant but here near the southern tip of Florida it should grow well most years IF there is no significant freeze. I think Simmonds is Type A and need a type B. I am interested in BETA but cannot find anyone whole sells this variety. Anyone know where I can find BETA avocado?

It is interesting how little information there is on these cold hardy varieites. I have had Joey for about 2 years and have recently acquired fantastic and poncho. The Joey is much more cold tolerant than Mexicola Grande. I actually got rid of the Mexicola Grande because it suffered so much leaf damage in our Northern California winters (zone 9b) with low temperatures around 25 degrees. The Joey suffered only slight leaf damage to the very new, tender growth. The older leaves were absolutely unaffected by these temperatures. So, the cold hardiness of this particular cold hardy variety seems far superior than traditional frost tolerant avocados. The real unknown is the fruit quality.

-Brett

This is my first post on this forum--I found this thread while looking for info on grafting avocados, and thought I'd chime in.

Regarding cold (and heat) tolerant avocados, my neighbor here in nw Tucson had two very large Zutanos in his yard (1 about 40' tall and the other somewhat smaller). They fruited well and he was pleased with the quality, but both trees recently became diseased and he cut them down.

I recently acquired a Wilma and an Opal from Bill Schneider in Devine, TX. He does not ship, so I had a friend purchase them for me. Both are small (2' & 3', respectively) and are still in pots; I plan to plant them in 2013 once the danger of a late frost is past. I would be very interested to know if anyone has grown either of these varieties alongside Gainesville, and how they compare in terms of hardiness and fruit quality.

It think I'm finally going to try a few this spring... Not that I actually have a whole lot of room for them.

http://www.chestnuthilltreefarm.com/Cold-Hardy-Avocados-3943.Category.html

If you can grow citrus most years, you can grow the most cold tolerant avocados. They also recover more quickly from cold damage.

Recently HD had Mexicola in stock. They were in 30 gal pots and were about 5 - 7 tall for $86. I brought the best shaped one home and now I'm scratching my head as to where to plant it.

While I was pondering it I did a bit of research and found some old studies that were done on the root stocks. West Indies vs. Mexican. The outcome was surprising. They concluded that one should use the Mexican rootstock all the time for cold hardiness and growth. The surprising part was the supposedly WI rootstock did not make the Mexican varieties grow any more vigorously which is what they though would happen. If you have WI or other rootstock just bury the graft 4-5 inches deep at planting and it will be ok. If there is any interest in this I can post the links at a later date.

One other item I read is if you have a large mature avocado of the mexican type you might want to graft a less hardy one to the lower branches. It was said that the canopy did a pretty good job of protecting the less hardy branch.

As with many trees cold hardiness is a function of age and it was mentioned to use soil banks to protect the trees when they were young.

Don't you need two?

Just to report on my first year with the avocados in the ground here in Virginia, it looks like all my trees have made it. We experienced two nights that hit 19 degrees and they all look okay. On those two nights I just threw an old comforter on top of the trees. The Brazos Belle looks the worst but I think it typically has weak looking growth. The Joey is blooming and what I call my Charleston Hardy looks the best and so far is the most vigorous. It also has a couple of blooms on it.

In my research I noticed a lot of these varieties go by different names. I wanted to make sure that I didn't buy duplicates of the same actual varieties. Here is what I could decipher with all of the hardy avocados I'm trying out:

Fantastic = Pryor *small green, good flavor
Lila = Opal = Holland *pear shaped green fruit
Joey = Joey Ricers *large black fruit
Poncho = Poncho *medium to large green fruit
Brazos Belle = Wilma *cylindrical black fruit
Charleston Hardy = Gainsville, most likely *medium green fruit?

I thought about trying Mexicola but I just don't think it has the extra couple of degrees of cold tolerance it would need to survive up here most years. I just might test plant one out back and see though.

I recently spoke with Bill Schnieder of Devine Farms in Texas about cold hardy Avocados. There were a couple of things I found interesting. One, true mexican strain does not need a pollinator and are self fertile. Their yield may increase with one but it is not needed. Two, the Avocado staying true to the Type A or B is dependent on a consistent weather pattern. He said in the deep south where it gets humid and then dry, cold and then hot it will affect the flowering cycle. He said only consistent weather cause consistent bloomimg.

I now have a seedling from a Mrs. Holland. Does anyone know if they come true from seed. There is no question as to the parents as there are not any avocados nearby.

Just an update.

I ended up planting the Mexicola on my west side 6' privacy fence. It will be sunny till mid afternoon there. I prepared for planting by digging a seven foot wide hole two feet deep. All roots and debris were removed from the original soil. I then layered pine bark compost and the cleaned native soil/sand. After about a couple of thin layers, amounting to about six inches, the whole thing was tilled with a Mantis type tiller. After throughly mixing the layer it was tamped. We continued doing the layer, till, compact until we had used all the original soil and we now had a foot tall mound to plant on. I planted the Mexicola one foot off center and buried the graft six inches. Opposite the Mexicola and perpendicular to the Suns path, again one foot off center, I planted a seedling from a Mrs. Holland tree. This particular seedling came from fruit off of a seven year old grafted tree belonging to Skeet. The cutting he used to graft that tree came from Dr. Manners (thank you) and of course Dr. Manners tree came directly from the original tree belonging to Mrs. Holland. Skeets tree has seen several Winters with 20 degree temps. After I have mine for several years and the trunk gets a little size to it I should have a cold hardy Avocado.

The Mexicola had three fruit when I bought it but lost two. The one remaing looks good and should mature on the tree.

Hmmm. For the first time I have ever seen, Lowes is selling Hass avocado trees here.