Yes, some people try to use the US zones for the UK but they work only roughly because being such a small island the weather makes a nonesense of climate to a degree. I am on the border of eight/seven and most of the UK is either eight or seven with some six in the northern mountains. Being on a hill I am colder than some places nearby. We are having night frosts now and thaws in the day.

Yes this one is in a damp place and has made a bush twelve feet high with really good form.

Do you have any experience harvesting from this plant?

@beenthere Sorry, no, but I know you use the bark, ground up.

I have no idea will get back to you.

I googled it and came up with this really interesting clip.

For a long time, it was a mystery how a winter-flowering plant would get pollinated. A witchhazel that happens to flower on a slightly warm spring when honeybees are making their first flights in desperate search of food might get lucky. That is not a reliable way to reproduce.

It was the renowned naturalist Bernd Heinrich who realized that there was a group of owlet moths (family Noctuidae) called winter moths that are active on cold nights. These moths have a remarkable ability to heat themselves by using energy to shiver, raising their body temperatures by as much as 50 degrees in order to fly in search of food. It is a group of these moths that pollinate witch hazels. The moths that pollinate witchhazel are several species of Eupsilia known as sallows.

It would be easy to conclude that this is a case of coevolution - both organisms having evolved to depend on one another. This is probably not the case - Heinrich observed that these moths mostly feed on bleeding sap from injured trees. So, the tree is dependent on the moth, but the moth is probably not dependent on the tree.

@Fernapple
That's fascinating indeed, that any insect would fly around on below freezing nights!