How to Grow and Care for Catmint

Catmint (Nepeta) is a genus of perennial herbs in the mint family that also includes catnip (Nepeta cataria). They are extremely easy-to-grow plants with few pests or problems. Nepeta has slightly aromatic gray-green foliage with a delicate, lacy appearance. Its billowing foliage is topped with spikes of flowers in early summer with repeat blooms throughout the season. The flowers can be white, pink, or lavender-blue.

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.

Catmint Care

Catmint is one of those plants that thrives on neglect. Many of the newer varieties of Nepeta are sterile hybrids that produce no viable seeds; a benefit if you don’t like the weedy, self-seeding habit of older catmint varieties. If you want to increase the number of catmint plants, the lack of viable seeds mean that you will need to either buy more plants or propagate new plants from divisions or cuttings.

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.

1. In the spring, find a section of the plant with undeveloped shoots and a good root system.
2. Slice it vertically with a spade. If the plant is very large, you can divide it into smaller sections.
3. Carefully dig up the divided section(s).
4. Backfill the hole so that the section remaining in the ground isn't exposed.
5. Replant the division(s) in a new location.
6. Water in well and keep the soil moist until the division has overcome the transplant shock and shows new growth, which usually doesn't take longer than one month.

Another easy way to propagate catmint is from cuttings:

1.  In the late spring to early summer, use a sharp knife or pruners to cut a healthy piece of stem four to six inches long.
2. Remove the leaves from the lower half of the stem. 
3. You can insert the stem in a small container filled with well-moistened potting soil or place it in a glass with non-chlorinated tap water.
4. Keep the cutting in a location with bright light but away from direct sunlight. Water regularly to keep the soil evenly moist, or replace the water in the glass every few days.
5. You should see new growth in the potted cutting or roots develop in the water-grown cutting in a couple of weeks.
6. Transplant the new plant into the garden or a larger pot.

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.

1. Start the seeds indoors six to eight weeks before the last spring frost in seed flats or small pots filled with potting soil mix.
2. Press the seeds into the potting soil mix and only cover the seeds very lightly with soil because they need light to germinate.
3. Pinch the growth tips of the seedlings once they are two to three inches tall so the plants grow bushy rather than tall and leggy.
4. When all danger of frost has passed, plant them in a garden bed or in larger containers.

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.