Catnip (Nepeta)

Catmint, Catnip

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.

I. Appearance and Characteristics 

Nepeta is a genus of flowering plants in the family Lamiaceae. The genus name, from Latin nepeta (“catnip”), is reportedly in reference to Nepete, an ancient Etruscan city. There are about 250 species.

The genus is native to Europe, Asia, and Africa, and has also naturalized in North America.

Some members of this group are known as catnip or catmint because of their effect on house cats – the nepetalactone contained in some Nepeta species binds to the olfactory receptors of cats, typically resulting in temporary euphoria.

Most of the species are herbaceous perennial plants, but some are annuals. They have sturdy stems with opposite heart-shaped, green to gray-green leaves. Nepeta plants are usually aromatic in foliage and flowers.

The tubular flowers can be lavender, blue, white, pink, or lilac, and spotted with tiny lavender-purple dots. The flowers are located in verticillasters grouped on spikes; or the verticillasters are arranged in opposite cymes, racemes, or panicles – toward the tip of the stems.

The calyx is tubular or campanulate, they are slightly curved or straight, and the limbs are often 2-lipped with five teeth. The lower lip is larger, with 3-lobes, and the middle lobe is the largest. The flowers have 4 hairless stamens that are nearly parallel, and they ascend under the upper lip of the corolla. Two stamen are longer and stamens of pistillate flowers are rudimentary. The style protrudes outside of the mouth of the flowers.

The fruits are nutlets, which are oblong-ovoid, ellipsoid, ovoid, or obovoid in shape. The surfaces of the nutlets can be slightly ribbed, smooth or warty.

II. How to Grow and Care

Sunlight

Catmint plants thrive in diverse sunlight conditions. Ideally, they flourish under full sun where they can receive six hours or more of direct sunlight daily.

However, they also adapt well to partial shade, most especially benefitting from afternoon shade in hotter climates. It is noteworthy to mention that, though these plants are rather tolerant, their bloom may be slightly less abundant in less sunny locales.

Regardless, in harmoniously balancing their sun exposure, catmint plants will present you with an enchanting display of lavender-blue flowers from late spring to midsummer.

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.

Watering

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.

Soil

While catmint plants exhibit hardy characteristics and can thrive in a broad array of environments, they prefer well-draining soil.

This drought-tolerant member of the mint family will flourish best when its roots can expand freely, safe from stagnating moisture. Adding compost to the soil will deliver necessary nutrients and improve drainage, promoting healthier and more vibrant plants.

Approximately 4 weeks after planting, it can also benefit from a balanced slow-release fertilizer, which continues to provide essential nutrients throughout the first growing season.

Despite these preferences, catmint plants are highly adaptable and can still grow in less-than-optimal soil conditions if required.

Fertilizing

Catmint plants are considered hardy and adaptable, requiring minimal attention in terms of fertilizer. During the first growing season, a light application of slow-release granular fertilizer mixed with compost can benefit new plants.

Applying it in late spring, just before the onset of the bloom period, can promote robust growth and abundant lavender-blue flowers. However, supplementing with fertilizer is not commonly required in subsequent years if plants are growing in well-draining soil enriched with compost.

Over-fertilization, especially with nitrogen-rich varieties, can lead to excessive foliage growth at the expense of flower production. Therefore, maintaining a balance is crucial for these plants.

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.

Propagation

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.

  • In the spring, find a section of the plant with undeveloped shoots and a good root system.
  • Slice it vertically with a spade. If the plant is very large, you can divide it into smaller sections.
  • Carefully dig up the divided section(s).
  • Backfill the hole so that the section remaining in the ground isn’t exposed.
  • Replant the division(s) in a new location.
  • 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:

  •  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.
  • Remove the leaves from the lower half of the stem. 
  • 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.
  • 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.
  • You should see new growth in the potted cutting or roots develop in the water-grown cutting in a couple of weeks.
  • Transplant the new plant into the garden or a larger pot.

Growing from Seed

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.

  • Start the seeds indoors six to eight weeks before the last spring frost in seed flats or small pots filled with potting soil mix.
  • Press the seeds into the potting soil mix and only cover the seeds very lightly with soil because they need light to germinate.
  • 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.
  • When all danger of frost has passed, plant them in a garden bed or in larger containers.

Potting and Repotting 

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.

Pests and Diseases

Common Pests and Diseases

Aphids

Common amongst many plants, gardeners might encounter aphids on new plants or fresh new stem growth of established catmint plants. These tiny insects suck the plant’s sap, causing distorted and yellow mottled leaves.

Encourage natural predators like ladybugs to your garden or use a mild pesticide to address the problem. Catmint is a hardy plant and can usually withstand minor aphid infestations without severe damage.

Rabbits and Deer

While catmint plants are generally known to be deer-resistant, the aromatic gray-green foliage and lavender-blue flowers of the plant can appeal to rabbits. Latex fencing or planting catmint close to walkways or human-activity areas can deter these pests. Gardeners also report that Walker’s Low and other similar varieties of catmint are more resistant to rabbit damage compared to others.

Fungal Diseases

Due to its member of the mint family (Lamiaceae) roots, catmint can be susceptible to some common mint family diseases including downy mildew and verticillium wilt.

Both diseases can cause yellowing and wilting of leaves and, in severe cases, may lead to plant death. Ensuring your soil is well-draining and your plants aren’t overcrowded can help prevent these diseases.

Additionally, compost and organic fertilizers can also strengthen your plants’ resistance to disease during their first growing season and beyond.

Common Plant Problems 

Brown Tips on Leaves

When you notice brown tips on your catmint plants’ gray-green foliage, it’s likely the result of too much direct sunlight. These perennials, originally from Asia and a member of the Lamiaceae or mint family, thrive in full sun to partial shade.

However, prolonged exposure to intense sunlight can scorch them, causing the tell-tale brown tips. To counter this, ensure you plant them where they can enjoy afternoon shade and protection from extreme heat.

Yellowing Leaves

If your catmint exhibits yellow leaves, odds are it’s dealing with poor drainage. As a species in the Nepeta genus, it requires well-draining soil to maintain its overall health.

Sitting in waterlogged soil can lead to root rot, a disease best avoided in your herb garden. To resolve this, make sure to amend your soil with organic compost or fertilize it with a well-balanced fertilizer to enhance its drainage capacity.

Inadequate Blooming

Late spring till midsummer is the typical blooming season for many varieties of catmint, with spikes of blue, pink, and yellow flowers that draw pollinators en masse.

If your catmint fails to bloom satisfactorily, it might be due to a mismatch between the plant’s climate needs and its environment. While the plant favors full sun, remember that it must be coupled with the plant being drought tolerant – meaning excessive watering could dampen its blooming prowess.

Matching the hardy catmint with the right climate requirements and well-draining soil will sort this issue out. It’s well worth the effort, as this deer-resistant and rabbit-resistant plant can beautify your walkways and garden mounds spectacularly when in full bloom!

III. Uses and Benefits 

Some Nepeta species are cultivated as ornamental plants. They can be drought tolerant – water conserving, often deer repellent, with long bloom periods from late spring to autumn. Some species also have repellent properties to insect pests, including aphids and squash bugs, when planted in a garden.

Nepeta species are used as food plants by the larvae of some Lepidoptera (butterfly and moth) species including Coleophora albitarsella, and as nectar sources for pollinators, such as honey bees and hummingbirds.

Catnip (Nepeta) Details

Common name Catmint, Catnip
Botanical name Nepeta
Plant type Edible
Hardiness zone 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b
Growth rate Medium
Sunlight Full sun (6 or more hours of direct sunlight a day)
Soil condition Clay
Flower color Blue
Leaf color Gray/Silver