I have grown Orthosiphon stamineus (aka Cat Whiskers, Java Tea) and my experience is that the one I planted in the ground didn't make it over the winter last year. The one I put in a pot stayed in my flower hut - not a greenhouse, it is not heated at all - during the winter and it died back there, but came back this spring. Very thirsty plant - I couldn't keep the one in the pot watered enough this summer, so as with all plants that need too much attention, it ended up in the compost pile last month.