I'd beg to differ Bob! You London types only 'think' you know the meaning of a real winter anyway! lol!

Put it this way, the garden that the Albizia is in, lies in the middle of a remote inland rural area on the bordering the New Forest. The microclimate is pretty dire with a short growing season and hard prolonged frosts in winter due to it being situated in a valley with forest oak, ash and beech trees on the southern, eastern and western boundarys with some tall hollies blocking the low winter sun. The clay soil is also saturated during the winter. I landscaped the whole garden 5 years ago. Last year, the first hard winter killed off a mimosa (Acacia dealbata) that was around 20' tall with a 13cm diameter trunk 1 metres up (Yes they grow fast, especially if you ameliorate the entire site with 60 tonnes of blended compost and install a groundwater drainage system). This year, with a wetter, prolonged cold winter all the green Cordylines were killed, not just the growing tips, the entire plants! These were around 6' with a 10cm trunk. Also a Melianthus was killed, roots and all. It got down to -16 on and off for two weeks, followed by prolonged wet and cold spells! Luckily the other one survived.

The garden does however get a lot of humid sunshine in mid summer.

The garden still looks great, as succession is taking hold, localised microclimates are developing and the valuable plants are starting to fill in. Trachycarpus are thriving, 7m tall Phyllostachys vivax with 6cm diameter stems, Chusquea culeou, Thamnocalamus crassinoides and loads of other rarer bamboos, Purple Cercis trees, Catalpa's, Japanese acers etc.

Now surprisingly the Albizia and the eucomis bicolor survive unscathed!!!

I think Bob is right, like a crepe myrtle, the thing probably will never flower in the UK as we don't have the length of season or temperatures, but it will survive pretty well given as much sun as you can afford it and protection from northerly winds! Either ameliorate the entire border it is going into or just plant it straight in the soil you dug out. Don't create a sump with a hydrostatic gradient and it will be fine!

I'm off to write a book...lol!