I used to be quite unimpressed by catmint, but now I have become a fan. I think it is because we have had more hot and dry summers of late, and the Nepeta species, hardy in zones 5 to 9, hold up well in droughts.
I use low growing catmints such as ‘Dropmore Blue', which is 18 inches tall, and Nepeta ‘Six Hills Giant', which has wonderful 18" spikes of lavender-blue flowers. They make good edging plants and groundcovers in sunny spots, and their soft grey foliage combines well with just about any other plant.
When catmints are in bloom they look like lavender plants but are much easier for me to grow. Nepeta nervosa grows to two feet and makes a good companion for strong colored perennials, but like all catmints, it must have good drainage. I love the useful pure white ‘Snowflake'. There are many to choose from, as there are over 200 in the species and increasing numbers of hybrids.
Cut them back after bloom and they will bloom again. Nepeta cataria is the one that cats like the best, but deer seem not to like these aromatic plants at all. So, I now love catmint—what is there not to like about a pretty, serviceable and deer-resistant plant that endures (once it is established) hot dry conditions?!