A gravel and stone garden and drought loving plant Hibiscus trionum

One of the last areas to have the 'no lawn' treatment has now been completed.  The section nearest the house has a layer of membrane under the stone,  and this is where I will be standing to hang out washing on our removable rotary line. Already I've been grateful that 'dropped' washing has stayed clean.  

 The area further away and  nearest the border where for now, I have some larger stones, will gradually become a free draining gravel garden in the sense that any little suitable garden plants that self seed won't necessarily to be removed, and I may well use the area to display some of the succulents during the summer period. I had salvaged these few stones from a friend's garden, as they were being taken away prior to to building.

Is this a mystery plant or will it prove to be a Callirhoe of some type?  Jean collected the seed from a 'well known' garden, and this is one of the plants that she successfully grew on.  It is growing rather well considering the very hot and dry weather, which is one of the characteristics of Callirhoe.  It does not however have the characteristic trailing habit.  It is setting seed, and as the flowers are quite distinctive with the purple centre and golden stamens, I hope to raise a few plants to bring closer to the front of the border.

The plant is doing well in a difficult position partly shaded by the evergreen Holm Oak during the early morning...I just can't keep up with removing the very slow to decay leaves, which the tree shreds in May and June.

If anyone reading this would like to help identify it and leave any comments, this would be really appreciated.  Thanks to an SOS on my gardening club facebook Amanda has come up trumps.  It is Hibiscus trionum, aka Flower of an Hour, and it took less than an hour for a response.  Thanks.

I have since read in a magazine article that this is an annual known as flower of an hour because its flowers bloom for just a few hours during the day before wilting.  I agree with its description as being a well branched plant with deeply grooved leaves that combines well with perennials.  The flowers are followed by hairy, bell-shaped seed capsules.  I shall see if they self-seed in the garden.  I have saved some of pretty seed heads, and will set some in the spring time.