Pretty pin cushions

We are staying down in Deal, Kent at present as our son, daughter-in-law and two grandchildren are having the back of their house knocked out and a new kitchen built and are using our place in London. Just along the road from us here is Walmer Castle, which has beautiful gardens which l love to go and wander around in. I don't know what these flowers are called but l think they look like jewelled pin cushions.