Sorry to come late in this topic that I had not read before. I send you two pictures of Gaura lindheimeri, white form, that I grow in my garden.
The first shows a flower see closely, in summer (the year before).
The second is made in october this year, and show an overview of Gaura in association with Salvia elegans (red, in the foreground), S. leucantha (mauve and white form, on the left) and S. involucrata 'Hadspen' (pink on the right). Gaura is in background with few white flowers here and there. It adds at the "vaporous" atmosphere...
Just a little precision : no free seddling at all. I cut Gaura about in november to let place at the other salvia, mainly S. leucantha, witch is full bloom and take all the place !