Plas Tan y Bwlch is the Snowdonia National Park environmental studies centre. They run a series of public and professional courses from this base, near to the village of Maentwrog. The gardens are mainly based on a steep hillside. The path takes you quite gently up past a series of stopping points where the leaflet explains items of interest. This works rather well. There are other steeper paths and I think it could take a few hours to do the whole area. On this our first visit we stuck to the path, but with a mental note that we will return.
Y Gwyllt in places, it is of a similar age and had many similar plants.
Like most postponed visits, I now wonder why I was so foolish to leave it so long. I think I will be returning soon.