Nepeta is a reliable perennial, very hardy and tolerate of all conditions it returns reliably each year. Commonly Catmint produces clouds of soft blue and mauve in a garden and is a viable alternative to Lavender where the growing conditions will not suit Lavender. There are some less common varieties flowering white and occasionally yellow, such as N.govaniana. To do well Lavender requires much drier conditions than Catmint, especially over winter. Lavender will struggle on heavier wet ground as a mediterranean plant it needs to be dry, well drained and sunny; contrast Catmint which will grow almost anywhere. Nepeta is native to a number of habitats and so is not fussy where it grows. Catmint will grow in sun or partial shade and in both moist and dry soils. If you are looking for a similar colour scheme to Lavender, but conditions are too wet, Nepeta is a very good alternative. It is also long flowering and sometimes produces a second flush of flowers.
The larger species Nepeta faassenii 'Six Hills Giant' will sprawl and can go a bit thin in the middle; to avoid this you can stake or as Catmint responds well to the Chelsea Chop reduce it in size earlier in the year. In late May or early June, depending on the spring, cut the plant back by about a third. This will delay flowering slightly and make for a more compact shrub.
Once planted Nepeta is really easy to establish. It has the added bonus of being very attractive to bees and pollinators, walk past a clump on a warm day and it will be buzzing with the sound of bees. It is a plant which thrives in almost any conditions and does not need feeding, in fact feeding can make it leggy. Apart from bees it does attract cats, who love it. If you are not a cat lover and don't want sections of your plant to be rolled in insert a few sticks, which will be hidden by the plant growth, whilst also serving to deter cats from taking a roll in the Nepeta.
Nepeta is best cut back after flowering, and when doing so if you look carefully at the plant you will see newer growth which foliage has a fresh look contrasted against the tired older foliage. I cut back just the old foliage, let the new growth through and this may also produce a small late flush of flowers, if the summer is good.
The intensity of the blue fades after flowering and its worth shearing off the dead heads as it will often throw up some new flower shoots. The foliage on Catmint can go a bit yellow later in the season so if its starts to look tatty, chop flower stems and foliage. It is a very tough plant. A really easy garden plant which rewards year after year and minimal maintenance. It is worth noting that Nepeta is drought tolerant.