I think you might be overestimating the warming effects of the ocean there. When the cold events hapen, the prevailing air flow is over the land from the N.W. and thus, you are unlikely to see any impact. Also, I live in North Florida, away from the coast in z 8b and have driven the exact area you mention during the past two winters. Both times I was struck by cold damage I observed to Washingtonia robusta, Syagrus(queen palm) and oleander that were unaffected at the same time here in Gainesville. Thus, I think zone 8a is more likely. Plus, look at the average lowest temps. at Jekyll Island, GA for comparison - even there zone 8 temps are recorded frequently. That said, I think you have a great idea and opportunity. The species that Resin have suggested sound good to me too, but I would also add Araucaria angustifolia. This species looks to be very promising for this area of the country. It loves heat and humidity (unlike araucana), yet seems very hardy. There is a 40'+ tree that is only 12 years old!! at the Atlanta Botanical Garden. It is in superb shape and obviously fast grower (compared to araucana). There are others here in Florida as well and they are very similar to araucana in youth and very primitive looking. A. bidwillii is worth a shot - we have a few here in north Florida, but have been known to die after exceptionally cold winters. Resin is right - no Agathis north of Orlando that I know of (I am trying A. atropurpurea, A. corbassonii, A. lanceolata, A. moorei, A. robusta, and A. vitiensis here)...Others to try include Dacrydium cupressinum (doing well in a number of collections in the SE), Dacrycarpus dacrydioides (I know Podocarpaceae - but still cool), Callitris rhomboidea (doing well near Atlanta)...

Thanks for all the pics of your very rare conifers, Sali.. I like them very much, but unfortunately all are not hardy in Germany. Hubertus Nimsch, a famous man in Germany ( Arboretum Guenterstal,Freiburg )visited several times all locations from all Araucarias ( NC, too ) and grew all species from there in Guenterstal ( in glasshouses).He also wrote a book ( in German )" Araucaria" with all the Araucaria-species and with very good fotos of all species in nature, cones and young plants in Guenterstal. Most fotos from Bernard Suprin ( NC ) and Hubertus N.

Picea glauca for the boreal forest spruce Struggling with that stringy bark. Maybe Cupressus lusitanica? Pinus greggii for the 'ugly pine'? Last is a Widdringtonia (cones with 2 pairs of scales), not a Callitris (cone scales in whorls of 3). W. nodiflora? Resin

Well conifers are tough generally speaking. What about broad leaved plants from NZ. Do any survive for you? I don't remember seeing Phormiums in the deep south...but I guess I could just have missed them. Amazingly a book about gardening in New Orleans claimed that Azara microphylla will grow there. Yep, a Chilean plant from the faraway land of eternally low dewpoints...but...related to willows so perhaps being in a weedy family explains the quite anomalous ability to survive intense humidity and hot, wet soils. So I was prompted to try one and indeed, it is unbothered by summers here in MD. One of the only Chilean plants you can say that for. (of course it is barely hardy enough for the winters, but I'll cross that bridge when I come to it) I wonder if you could grow Freycinetia banksii? Again, maybe being from a strange family, even for New Zealand, might help. Good luck finding it! There are other, more tropical members of that genus too.