The Right Place
Hybrid catmint is a sturdy plant. It is hardy as far north as the Canada border (zone 3). It can handle winter temperatures as cold as -20° F or more.
Hybrid catmint needs full sun or partial shade. It tolerates heat very well, but is not happy in areas that have humidity along with hot summers. In the spring plant seedlings in average, preferably somewhat sandy, well-drained soil that has been loosened with a trowel down at least 8 or 10 inches.
Planting Nursery Stock
Choose an overcast day or wait until early evening to set out the young plants so that they are protected from hot sun during their first few hours. Remove them from their containers (unless they are peat pots) and dig holes 12 inches apart roughly as deep and wide as each transplant's ball of soil and roots. Set each seedling in its hole, taking care that each is at the same depth that it was in its former container. Firm the soil gently around plant stems and water generously.
Since hybrid catmint is sterile and therefore does not produce seeds, the best way to acquire more plants is to divide existing clumps. After 3 or 4 years plants spread into overlarge clumps. In the spring dig up a mature clump of catmint enough to expose the root system. Cut or pull apart smaller chunks of plant, taking care to include sufficient roots to support the smaller plant. Return the original clump to its site and replant the separated chunks around the yard following the procedure described above. Water well until they are established.