Sea pink.

Plant of the week: sea pink | Life and style | The Guardian
What is it?
A rugged coastal plant won't balk at poor soil, exposed sites or a good lashing from the wind.
Its neat carpet of evergreen leaves is topped with lollipops of candy-pink flowers from May to September.
Sea pink (also known as thrift or Armeria maritima) makes perfect ground cover for gravel gardens, border edging or planting in a trough: I'm getting some to put on my green roof.
Expect a height and spread of around 30cm x 30cm.

Plant it with?
Thrift will rub along nicely with other drought-tolerant toughies, such as blue fescue grass (Festuca glauca), dusty miller (Lychnis coronaria), and wormwood (artemisia).

And where?
If you have a coastal garden and struggle to grow much, this British native is a banker.
It will not, however, enjoy life on poorly drained soils or shady spots.

Any drawbacks?
As Derek Jarman, in whose Dungeness garden thrift thrived, pointed out, "It's going to leap about."
In other words, if this plant likes your garden, it will spread and spread.
If it fails to spread, divide plants in autumn or early spring to make more.

What else does it do?
Bees, butterflies and other pollinating insects will be drawn to its nectar.