Grass growing well in the UK in December

This is the second year that we have had out 6m tall Fairy Bell Christmas tree (cone shaped led mesh) on the front lawn.   This is the second year that I have had to mow the lawn where the tree stood.  All that extra light made the grass grow!   Another observation I have made is that the houseplant Rhoicissus ellen danica is very, very hardy.   I left one outside hidden behind some terracotta pots and it's still green and surviving despite having a sprinkle of snow and despite being outside in sub-zero temperatures.  That's a hardy houseplant.