Old canna blooms are cut off the stalks during the summer. Leaving them to produce seed pods at this time of year does not discourage new flower buds. The colder weather tends to do that.
Spent liatris stalks are kept around because I want something in that location. If the stalks were cut back, there would only be an empty hole in that part of the garden. The resulting seed stalks look interesting, and since they bloom only once during the year from a root cluster, cutting them back does not result in more blooms or branching stems.
Sometimes, seeds can be as beautiful and interesting as the flowers.
Blooming: canna, basil, dwarf zinnia, lime nicotiana
Harvested: 10 peppers & 2 tomatoes before frost,