There are two plants in the Main South Garden. This one is by the gas meter. (MNG2021#01) [Note these seem more purple than the red of a Niobe?]
"A Proven Winner® Proven Selection®, Clematis 'Niobe' These 4-inch blooms simply radiate bright color from late spring to early autumn. One of the best where summers are especially hot, it keeps going when lesser plants melt out in the heat and humidity." -jacksonandperkins.com