A new flush of growth and flowers often occurs. Plants can become vigorous and spread over or out of boundaries, so prune as needed. The most common, and many think the prettiest, is the Six Hill Giant catmint. The dark violet flowers called racemes are often 10 to 12 inches long and are borne on plants 2 to 3 feet tall. Dropmore Hybrid is smaller but not as easy to find.
Porcelain has attractive light blue flowers with blue-gray foliage.
Just recently I have seen beds with a variety called Blue Wonder that was very pretty. Don't forget about other recognized winners like Lamb's Ear, Mexican Bush Sage and Dusty Miller. Recommendations on this web site do not endorse any commercial products or trade names.