still growing

shortly to be the winter solstice and a chinese elm I popped into the ground to perk it up again on the advice of the good boffins on here is still vigorously growing. Will this cause mischief if it doesn't get it's head down over winter?

If it is hit by a sudden frost, which is likely looking at the forecasts, it will suffer a bit of tip dieback. This is usually just the softer parts of new growth. Parts that have lignified or turned stiff and changed colour will usually survive. If you are worried about it, throw some horticultural fleece or other insulation over it ovenight and remove once temp's climb above freezing. It will soon enough decide it is winter and stop growing. Mine only lose a tiny proportion of growth if they are hit by sudden frosts and all survive just fine.

I thank you.

it's still in full leaf and colour. Covered in frost. bizarre.

I would'nt worry too much. Chinese Elms sometimes stay in leaf until the spring, when all the leaves drop off and are replaced by a fresh crop.