![Cotinus coggygria [CC-BY-SA-4.0 Steve Cook]](https://www.polypompholyx.com/wp-content/uploads/2017/07/Cotinus_coggygria_autumn_leaf-267x300.jpg)
In the days when potted plants were more than just disposable land-filler, my Nan would try to force her wizened poinsettia to flower by sticking it into a bin-liner with some apples every night from October until December. Sum total of flowers she ever saw: zero. Ho hum. But how many poinsettia flowers can you …