Pure clay is probably a bit of an exageration, Vinlander. Although the soil is very heavy and the subsoil not far below.
Some plots are worse than others depending on how long they have been left fallow or whether fruit trees or bushes have been planted helping to prevent the soil migrating downslope. I did amend the soil for the goji along the lines, though not as extensively, as you suggest.
I was put off the custard banana (Asimina triloba) because it looks like you have to have two different kinds and hand polinate.
https://www.youtube.com/watch?v=SXN3WB2ZPYIBut I would like to try them if possible, not least because the fruit is spectacular. Perhaps one for next year along with persimmon kaki.
The unusual fruit I now have in no particular order are:
Arctic Bramble
BEACH PLUM Prunus maritima. rare, sounds interesting.
SALMONBERRY Rubus spectabilis
Thimbleberry Rubus odoratus
SILVER-STEMMED BRAMBLE Rubus biflorus
Black chokeberry, aronia. variety Nero. (I have since found a fruiting aronia on a disused plot) The fruit has a robust good flavour. Claimed to be better cooked but I did not find them too unpleasant fresh.
Honeyberry, five different varieties so cross pollination should be good.
Mahonia aquifolium, edible berries, also want some berberis, vulgaris, aggregata, already have darwinii.
Saskatoon (Amelanchier alnifolia) variety northline, I also picked up three seedling saskatoon from ebay for a very good price. These are self fertile but are said to crop better with others in the vacinity. Looking forward to these.
Ribes aureum, also ordered a named variety from lubera (they call the fourberries) so have two kinds. These sound excellent for the bee friendly flowers as much as the fruit.
Tayberry. Unusual to me.
black raspberry. Really looking forward to these.
https://www.youtube.com/watch?v=BKRI7On08L4&index=1&list=PLblOtw3UOFliiCK91iLMUtnol5SS13uMlhttps://www.youtube.com/watch?v=0YSAotXw8X0&list=PLblOtw3UOFliiCK91iLMUtnol5SS13uMl&index=3Yellow raspberry, variety all gold.
Balloon Berry Rubus illecebrosus, Spectacular looking fruits. Insipid taste apparently
Cornelian Cherry Cornus mas
Autumn Olive eleagnus umbelolata – Red Cascade , not Big Red as mentioned earlier. Also looking for goumi e. multiflora
Chilean Guava – Ugni
Chilean Guava – Flambeau Both in pots for now.
Also goji as mentioned.
I also have a Chaenomeles cathayensis planted last year so looking forward to a fruit or two this season coming.
Upon your recommendation I will look out for a pineapple guava. An online search uncovered a couple of named varieties. (again I was Put of by tales of poor cropping)
A couple of japanese plums are ordered from this site.
http://www.gb-online.co.uk/prestashop/category.php?id_category=123The red fleshed plums you buy in the supermarket are japanese plums rather than the european ones. (czar, opal, victoria, etc.) They also sell rootstocks and scions so may try my hand at grafting next winter. (order already in for this year)
And to top it off about six varieties of cultivated blackberries inspired by this:
https://fruitforum.wordpress.com/2009/01/11/which-blackberries-are-best-suited-to-the-uk/Digeroo, I asked if you know a goumi source and you do. Not too sure about the lack of fruit. Perhaps you need another for pollination.