Macadamia tetraphylla. A friend of mine gave me some macadamia seeds from australia that i grew. I had very little hope of growing these plants since they come from australia, but to my great surprise they seem to show an amazing frost tolerance. They just survived the latest cold spell of up to minus 8 C (17.6 F) 

They are growing in pots in my polytunnel and i think had they been outside they probably would have died. One thing that is not good for tender plants is to have wet roots, another thing is the wind.

Notice the one plant i planted in commercial soil, that stayed rather wet, has suffered much more frost damage than the others standing in more sandy, draining soil. I grew them last year from seed and i will see how they will grow this year, for their growth and energy came from the seed and now their roots will have to sustain them. Eventually, when they will get bigger, i will have no choice than to plant them out.

Realistically i have very little hope of them being able to grow here outdoors, and much less make nuts,

but i will try nonetheless.