Not sure that kind of garden that is? you mean something that looks creepy? In which case- a Harry Lauder Walking Stick shrub. Black mondo grass. Moss covered stone statues..

When I think ancient/witchy garden I automatically think tons of medicinal herbs and lots of variety. Being in lower mainland BC you've got a climate that makes it ideal to keep an herb garden that would be suited to something grown in old England.

wormwood, tansy, yarrow, mandrake, poppy, monkshood, sage, henbane, datura,, belladonna, foxglove to name a few.