It will be very difficult, and likely impractical, to grow any intergeneric hybrids in zone 6. US852 and TaiTri might be the only ones that would have any chance of making it, and even then I'd strongly recommend planting in a protected spot, somewhere that won't get too much wind, and putting a pile of mulch and a cover on it over the winter. Probably close to the wall of a house would be good, surrounded by other nearby bushy plants. Bear in mind these two are not exactly "delicious" tasting. TaiTri is not very much better in taste than poncirus, while US852 has a bit of off taste and is nowhere near as good fruit quality as the crappiest mandarin you might ever find in a supermarket. Though I did see a video where one very adventurous enthusiast claimed he was able to "enjoy" eating them. (full of seeds of course)

Here is a proposal for your trip. Places with a *** are really a must. Freiburg (Germany) Arboretum: 100 yo Pseudotsuga menziesii. http://www.biologie.uni-ulm.de/extern/guenterstal/farbotxt.htm Arboretum du Vallon de lÂAubonne, West of Lausanne. http://www.arboretum.ch/ *** Lake of Derborence, Canton du Valais : old growth forest of Abies alba, untouched for more than 2 centuries. *** Aletsch forest of Pinus cembra. You will go to Morel (after Brig) and take the telecabin to Riederalp, then a second telecabin to Moosfluh above the Aletsch glacier. Also Larix deciduas and Juniperus alpine and Picea abies. You go back on foot to Riederalp. You can have a hot drink in the Hotel/Restaurant in Riederfurka. If the weather will not change unfortunately already too late. I would not recommnend to go there if snow is present. http://www.wettercam24.ch/d/channel1/riederalp/index.shtml Go back to Brig and take the Simplon Pass. (If it is closed you will have to put your car on the train to Domodossola.) *** Lago Maggiore between Switzerland and Italy. *** In Verbania  Intra, look for the ferry boat to Laveno, and find the Villa Taranto Botanical Garden just right side of the docks on the shore. http://www.villataranto.it/home_eng.htm *** Living the car in the park place, take the boat to Isola Madre. http://www.pinetum.org/Madre.htm Take the ferry-boat to Laveno (running until 24h00) and you can spend the night in Cerro at the B&B: www.polidora.com *** And visit the 7 hectares Botanical Garden the next morning. Go back to Switzerland on the same side of the lake until San Nazzaro where is the Otto Eisenhut Nursery and Botanical Garden. http://www.eisenhut.ch/location_en.htm Then you can go in the Graubunden to the one Swiss National Park. http://www.nationalpark.ch/snp.html If you will send me a private message (pinetum(at)hotmail.com), maybe I can send you a useful recommendation. Driving through the Alps and if you have the choice (snow is always possible), do not take the tunnels, but go for the passes. (I fear though that it will be too late, already some passes are closed.) http://www.swissinfo.org/fre/inforoute/index.html?siteSect=490#pass Even the tunnels could be difficult. See: http://www.lematin.ch/pages/home/infos_services/info_route (gesperrt = closed) Conifer diversity is low in the Alps. Picea abies is everywhere. Pinus sylvestris is local sometimes already in the valleys. Pinus cembra is rare and to be found only at high altitude (timberline is around 2000m.) usually away from the main roads. Pinus mugo is everywhere, but more frequent at high altitude where it grows low. Larix decidua is frequent and goes to the timberline. It is the pioneer species around the retreating glaciers. Hope this helps. Here is a link that might be useful: Conifers in Switzerland

Fabaceae: I have the trifoliate-orange cultivar 'Flying Dragon'--about 4 ft high so smaller than the regular plant, columnar habit, with very contorted and twisted stems and branches. And savage thorns (citrumelo has inherited those.) The fruit is less than golf-ball size with a thick, hard rind and almost no pulp, just seeds. I'm not into sugary foods so haven't made marmelade, but have grated rinds for zest which is very bitter. Flowers typical for Citrus, highly scented. Ripe fruits are fuzzy yellow, not orange. In my book very worth growing. It flowers fairly late in spring so avoids heavy frosts (so far). For fresh eating I have two Meyer lemon trees and some kumquats. These are outdoors in summer and in the house in winter. Very reliable. I've tried many other citrus with less than satisfactory results. The citrumelos are in very large containers and have not flowered. Hopefully they will if they can get established in the ground. It'll be a learning experience. What citrumelo might do here is one thing--after 22 years here I have learned not to rely on horticultural information from "authorities" who have never gardened in the middle Rio Grande valley. This place lends new meaning to the whole shtick. By the way, I see that the new Flora of China has transferred the trifoliate-orange to the genus Citrus, making Poncirus trifoliata a synonym of Citrus trifoliata.

I am glad they all lived. I hope this turns out good as the trees gain size and cold resistance. Steve