Mystery flower.

At last we are getting some colour and spring flowers in the garden.The old favorites,bluebell etc,but we have a plant that has come up several years running and I do not Know what it is,I can not find it in any flower books we have.I am hoping some one will recognise  it,I would love to know what it is.

Each single stem has one round head of these pink flowers,they have no scent.
The stems are thick,pink/red in colour and covered in silky hairs.they grow to about two feet high and when the flowers are gone ,the leaves grow.The leaves are huge and resemble rhubarb leaves,in the autumn they turn red and orange,the plant by this time is over three fee high and very dense,if not thinned out it takes over the flower bed.

I am looking forward to your help identifying this monster plant.

We have plenty of bluebells but this year I have found these pink bells as well.

The pear tree on the cottage is coming into blossom and the rockery is coming into life.