Pruning Catmint 'Six Hills Giant'

The key to keeping 'Six Hills Giant' tidy and encouraging a second flush of flowers is to cut it back hard after the first flowering wave finishes. This typically falls in July or August, once the main display of blue-purple blooms has faded. Use garden shears or hedging shears to shear the whole plant back by about half to two-thirds of its height, removing spent flower stems and tired foliage. This may seem drastic, but catmint responds vigorously, producing fresh green growth and often a second, smaller flush of flowers in late summer or early autumn. If you prefer a slightly less severe approach, you can deadhead individual flower spikes as they fade, but this is time-consuming on a plant of this size and won't stimulate the same rejuvenation. The shearing method is far more practical and keeps the plant compact and shapely. Without this mid-summer cut, 'Six Hills Giant' can become sprawling and untidy, with stems flopping outward and foliage looking shabby. In late autumn or early spring, tidy up any remaining dead stems and foliage, cutting back to just above the emerging new growth at the base. Some gardeners prefer to leave the old stems over winter to provide a little protection for the crown in very cold spells, then clear them away in March. Either approach works well. No other pruning is necessary. This is a low-maintenance perennial that doesn't require complex shaping or thinning—just that one decisive summer shear to keep it performing well year after year.