Or leadwort or plumbago (Chinesische Bleiwurz)
It looks fairly fragile, but looks can be deceptive. It is very frost-hardy, and despite the drought for over 7 weeks in the summer, in mid-August it started producing fresh leaves and buds. By late August the first flowers opened. All through September it flowered its heart out. Now the best part comes, in October… still producing these beautiful blue flowers the foliage also starts to turn reddish brown.
It is wonderful ground cover, looking pretty next to late Nigella and Acquilegia leaves. But it does need a well-drained sunny spot to do well.