On 22/07/2015 5:56 PM, Nick Maclaren wrote:
People unfamiliar with the conditions should look at the Climate FAQ
(www.u-r-g.co.uk/faqclimate.htm). Measuring the hardness of winters
by lowest temperature alone doesn't map well into plant hardiness,
and our short, cool summers are as much of a problem as the winters
to many plants (and especially fruit).

Janet might be able to grow Chinese gooseberry (Kiwi fruit), but
I suspect not, and doubt very much that it would fruit. It does
in the south of the UK, and in a warm position (e.g. on a suitable
wall). Similarly, avocado might grow on the south coast or even
in the smokes (er, Middlesex), but the same applies.

Unless the OP plants their 12 inch avo, they will never know if the
plant will grow and fruit or if it will not.

A lot of garden advice is "knowledge" that is simply recycled endlessly
without that "knowledge" ever being put to the test.

I've been told repeatedly (as do the books written by nearly all
supposed experts) that I cannot grow either lemons or mandarins in my
climate. I now have a fruiting lemon and this year my mandarin tree is
covered in fruit. Whether the mandarins will yet get to be eaten is to
be seen. I suspect I should have taken some off as the amount of fruit
is way too much for the size of the tree.

I planted both of those things that I supposedly can't grow after a)
reading a book by someone who had set out to prove that he could grow a
range of fruit (including sub tropical) in a place that I'd consider to
be a cold climate, and b) after I'd seen 2 huge mandarin trees growing
and fruiting where they supposedly never could survive and much less
produce fruit.

I planted my mandarin tree when I went to visit a woman who had these 2
huge mandarin trees on either side of her front door. I said to her and
I KNEW they wouldn't grow where she lived. Her response is that every
single gardener who visited her told her the exact same thing and the
mandarins just kept on ignoring such advice.

There are numerous techniques that can be used to get plants to grow
where they supposedly won't. Just one example I've seen is where grapes
were grown in 6 ft deep slit trenches with corrugated clear roofing
sheets on top of them. The grapes were growing well and had fruit and
the owner of those grapes had been told that he couldn't grow grapes in
his climate so he set out to prove he could do it. His worst problem
was kangaroos jumping on the roofing and falling through.

Since the OP asked for any advice, mine is to plant their 12 inch plant.
It may grow. It may even fruit. They won't know until they test it
out.