The purple flowers are a type of Cranesbill (common name) called Geranium Rozanne (which is the Latin or botanical name.) They are very long blooming even in the heat and humidity we have in the DC area and they are perennial, which means that they come back every year after going dormant in the winter.

I love that you used the Cranesbill. They are one of my absolute favorites and I use them in mass like this often. Your overall choice of plants is what makes this space so lovely; you've taken a clean, simple patio and turned it into an elegant retreat. Very glad I came across this one...

Thank you, Outdoor Dreams!