I don't have Powis Castle but have the ordinary artemesia growing in my garden and it does perfectly fine in light to medium shade.

Thanks, Dawn! I decided to try and take a cutting that had a bit of root attached and transplant to that spot. Just did so yesterday. Here's hoping!

I seem to recall (I can't keep it through winters usually) that it roots easily from softwood cuttings like in June.

I've moved rooted branches that way too. It is easier for me than messing with rooting cuttings at a busy harvest/canning time.Aremesia does seem to root very easily.

Mine "had a baby" last year and I dug it up and gave to a friend for her new home. It did very well. This is a little bit different, though. Hoping it takes.