Here’s how to keep your plants looking like the cat’s pyjamas:
Well drained, especially in winter; ideally on the sandy side.
Full sun preferred, part shade tolerated.
Feeding & watering
Keep fertilizer (especially nitrogen) to a minimum in all but the poorest soils. Drought tolerant in most situations; water only if plants start to droop.
Clip back in July for repeat flowering until frost. If necessary, control spread by cutting around clump with a spade; severed pieces can be replanted elsewhere.
None—unless you count cats, which may snack on it and roll in it. Most cats, however, won’t chew catmints to the ground or go bonkers around them.
Powdery mildew may appear in late summer. To prevent it, water at soil level to avoid wetting leaves; provide good air circulation.
Divide clumps in spring. Most hybrids have sterile flowers, but N. cataria, N. nervosa and N. subsessilis can be started from seed in a cool greenhouse.