The one avocado I know of, growing in our climate, is in Charleston. It is a Gaineville, and is at least 25' tall. I have a potted Mexicola, planted in a pot, which I will plant out next spring. Gainesville and Mexicola are reported to take around 15 degrees F.. Hardy varieties, such as these, are the only ones I give much of a chance of making it in southern Beaufort County. Even then, you have to live with the fact that we will eventually get a killing freeze that will do them in.

It is my opinion that mango is not going to make it here. Last winter was not a normal winter for us - here in Port Royal it never got below 30. A normal winter will get into the low 20's sometimes below. Hilton Head is no exception.

Key limes should be treated as a pot plant, unless you are prepared to take special measures to protect them from the cold.

Ned

Mangoes grow from 30 to 100 feet. But of course you have the grafted ones.
Matured trees can withstand 25 *F for a few hours but young mangoes can be killed at 29 to 30 degrees just for a few hours.
Very delicate.
I had one growed for 2 years from a seed but I neglected it once one night when the tempt dipped down to 34. Did not recover.

Laaz:

Here’s my other palms planted in my front yard but I don’t know their names. I just got them from friends while young.



And here’s queen palms planted last year



And here’s the queen palmms of my neighbor but they don’t have fruits yet.

Ned, if you can get your Mexicola to adapt in the ground, can
be as little as 3 years and as much as 6 years in some locations,
I think the tree can endure temperatures down to 6 degrees for
a couple of hours. You may still see some severe twig and branch
damage but the roots should still remain alive if they have adapted.
The key is for Avocados that came about as rooted cuttings as if
after a severe freeze we get some mild cooling temperatures for
our lows the following years the plant can come back for us.

I have not stayed up to date on cold resistant rootstocks as the
trend in the nursery industry for a while was to have dwarfing
rootstocks that could lead to a scale down in the size of these
plants to better enable people wanting to grow Avocados in
containers and for home gardeners that wanted a smaller
sized plant, rather than "breed" cold tolerance into the plant
once the Avocados were in the ground. As a consequence
for the production growing areas there was no real need to
work on cold resistance for the most part until people in
marginal and colder growing areas wanted to grow Avocados
themselves, mostly in a home garden.

The Mango may be able to make it in a large greenhouse or
as a container plant, the latter much like I had to grow my
Cashews when I had them. I got some nuts but the plants
did not live long for me here. Too cold here and I made
some mistakes growing them that may have contributed
more than the cold did to their demise. Did not realize
it then and when I did it was too late to rescue them but
I have a better idea what not to do for them in case I try
again anytime soon. (This is the mentality we had when
we brought in plants to grow that we knew we would have
trouble growing but we tried anyway as we learn a few
do's and don't along the way to give us a better chance at
having some of them live. Success is measured in having
one eventually live for us after others along the way didn't
make it).

Not sure I should even mention this as it is just an observation
that a few of us had but I learned Key Lime and Mexican Lime
to be slightly different in their physical appearance. We felt
one was a form of the other and was not distinct enough to be
a separate cultivar. I've felt for some time that the Mexican
Lime can handle slightly cooler temperatures than the Key
Lime can. We should see less yellowing of the leaves and
less leaf drop when the temperatures get cooler. We should
see earlier in the season new rejuvenate growth come back
for us from the Mexican Lime than the Key Lime will for us
here in the San Joaquin Valley. If given a choice to grow here
I'd go with the better cold tolerance of the Mexican Lime any
day. People elsewhere may prefer the Key Lime and that is
fine by me. The Key Limes fruit can stay longer on the tree
before falling than a Mexican Lime will for us here also.

Jim

Avocado is Persea americana. I was talking to a friend who pointed out that there is native tree here, called the Red Bay (Persea borbonia), that is related to avocado. I wondered if anyone knows if they might be graft compatible? There are quite a few growing near our nursery.

Ned

Below are links to serve as a starting point.
The third and fourth links may take longer
than the others to load in.

It seems that there has been some work done
looking into Persea borbonia as a possible
rootstock for fungal disease resistance.

Jim

Persea borbonia

http://www.floridata.com/ref/P/pers_bor.cfm

Interspecific Hybridization in and Chromosome Numbers in Persea

http://www.avocadosource.com/Journals/ASHS/ASHS_1954_63_PG_239-242.pdf

Avocado Rootstock-Scion Studies

http://www.avocadosource.com/Journals/CA/CA_1955_V9_N2_PG_11_12.pdf

Graft Compatibility In The Genus Persea

http://www.avocadosource.com/cas_yearbooks/cas_42_1958/cas_1958_pg_102-105.pdf

Soil Borne Pathogens of Avocado

http://www.avocadosource.com/Journals/ITFSC/PROC_1976_PG_75-82.pdf

Prospects for Integrated and Biological Control of Avocado Root Rot - Some Overseas Impressions

http://www.avocadosource.com/Journals/SAAGA/SAAGA_1979/SAAGA_1979_PG_17-20.pdf

Interesting. Thanks Jim.