When to plant Catmint?
Best month and method — Nepeta x faassenii
Plant your catmint in March, April, May, September and October — the optimal month is usually May.
You're in the planting season right now — a good moment to start.

Spacing
45 cm
≈ 5 plants
For an X m² border, calculate: X × 5 plants.
Step by step: plant catmint
Catmint thrives in full sun and well-drained soil, making it ideal for sunny borders, gravel gardens, and edging paths. It tolerates loam, sandy soil, and chalky soil equally well, but good drainage is essential—waterlogged roots will quickly lead to rot. Choose a spot that receives at least six hours of direct sunlight daily for the best flowering and compact growth. Plant catmint in March, April, or May for establishment before summer, or in September and October to take advantage of autumn rains and allow roots to settle before winter. Space plants 45 cm apart to allow for their mature spread of 40–60 cm; they will knit together to form a soft, billowing mass within a season or two. Prepare the soil by removing weeds and digging in a little grit or sharp sand if your ground is heavy clay. Dig a planting hole slightly larger than the root ball, set the plant at the same depth it was growing in its pot, and firm the soil gently around the roots. Water thoroughly after planting to settle the soil and eliminate air pockets. If planting in spring, water regularly for the first few weeks until you see new growth. Autumn-planted catmint needs less attention but should not be allowed to dry out completely before winter sets in. A light mulch of gravel or grit around the base helps suppress weeds and improves drainage, especially on heavier soils. Avoid rich, moisture-retentive mulches like compost, which can encourage soft, floppy growth and reduce the plant's natural drought tolerance.