Most catmint varieties have a somewhat sprawling growth habit, making them nice plants for edging planting areas and for running along paths. However, a few tall-growing varieties, like ‘Six Hills Giant’, have a more upright growth habit. As with many scented, gray-foliage plants, catmint is deer-resistant. It grows quickly and in most climates can be planted from spring to early fall. Choose a full sun location with well-draining soil. A lean soil and somewhat dry growing conditions will encourage both more flowers and a stronger scent. Too much fertilizer will only make the plant grow lots of flimsy foliage. As with most plants, the mature size of catmint depends on the variety you are growing. Most catmints are floppy, bushy plants that mature at about 10 to 24 inches tall and 12 to 24 inches wide. However, some varieties are more compact, and others that will grow four feet tall and three feet wide. New catmint varieties are being introduced regularly, so the best thing to do is to shop around and read the plant tag before you buy. Expect your Nepeta to start blooming in early summer with repeat blooms throughout the growing season. Deadheading or shearing your plants will produce stockier plants and a lush second bloom. Catmint is rarely bothered by any pests and diseases.
Light
You will get the best flowering if you plant your catmint in full sun, however, the plants will also grow well in partial shade.
Soil
Humus-rich, well-draining soil is ideal. Many species grow easily in a wide range of soil types, including dry clay and sandy or rocky soil. It’s not fussy about soil pH, growing well in a wide range (5.0 to 8.0).
Water
First-year plants need frequent watering, every couple of days during the first week, then about one inch of water per week for at least one more month in the absence of rain. Once established, catmints are drought-tolerant and don’t need watering.
Temperature and Humidity
Catmints like cool temperatures and benefit from afternoon shade in warm climates. They are often not tolerant of high heat and humidity.
Fertilizer
Catmint is not a heavy feeder. In the first year after planting, a handful of compost, added to the plant’s base in the fall, is sufficient. In subsequent years, the plant needs no further fertilization.
Catmint Varieties
Nepeta x faassenii ‘Six Hills Giant’ is one of the tallest-growing cultivars, It has lavender-blue flowers and grows up to 36 inches tall and 30 inches wide, so be sure to give it plenty of room in your garden. Nepeta subsessilis ‘Sweet Dreams’ features pink flowers with burgundy bracts. It likes a bit more water than most Nepeta varieties. It grows to two feet tall and three feet wide. Nepeta racemosa ‘Walker’s Low’ has lavender-blue flowers with eight-inch spikes. This 2007 Perennial Plant of the Year reaches two feet tall and two feet wide and is one of the hardiest and most reliable varieties. Nepeta racemosa ‘Little Titch’ is a dwarf variety with pale blue flowers. It is just as long-blooming as many of its larger cousins, but its growth stops at about eight to ten inches tall and 15 inches wide.
Pruning
Catmint plants will gracefully spill over walls and walkways. Most catmints will repeat-bloom if they are sheared back after their initial flowering. Some won’t provide much of a second show, but their foliage will be refreshed and tidied by the shearing.
Propagating Catmint
Catmint plants will continue to grow and bloom well for years. But if you’d like to divide them to make more plants, all Nepeta varieties respond well to division. Another easy way to propagate catmint is from cuttings:
Growing Catmint From Seeds
If you want to grow catmint from seed, make sure you gathered the seed from a non-hybrid variety or purchased the seed from a reputable seed company.
Potting and Repotting Catmint
Like most types of mint, catmint grows well in a container. In fact, many gardeners prefer to grow it in a container because it prevents the plant from spreading. Use a pot at least 12 inches in diameter with large drainage holes. Unglazed clay is ideal because it enables excess moisture to evaporate. Fill the pot with a quality potting mix, which might have a slow-release fertilizer mixed in. Water it slowly and thoroughly until the soil is evenly moist. Like all container plants, catmint needs regular watering to keep the soil moist, even though it’s drought-tolerant when planted in garden beds. When roots grow out of the drainage holes or the plant becomes root-bound, it’s time to transplant it to a larger pot or divide and replant a section in a same-size container with fresh potting mix.
Overwintering
Catmint is a hardy plant up to USDA cold hardiness zone 4 (-30 to -25 degrees Fahrenheit) and overwintering is only required when you grow it in containers in cool climates because a winter freeze can kill the roots. Bring the container indoors when the temperatures drop in the fall and place it in a cool room near a bright window. Or, if all your rooms are well-heated, overwinter it in an unheated garage. Either way. cut down on watering during the winter but don’t let the soil dry out completely. The plant will go dormant and bounce back in the spring.
Common Problems with Catmint
Catmint is rarely bothered by any pests and diseases. The plant is low-maintenance and easy to grow and propagate, some of the many reasons catmint is so popular with gardeners.
