Catmint is a low care perennial plant with a long bloom time that is measured in months, not weeks. The pretty flowers attract pollinators, yet it’s rarely bothered by critters like deer and rabbits. And while it’s easy to grow, knowing when to cut back catmint is essential for promoting lush, healthy foliage as well as non-stop flowers. In this article you’ll learn the 3 options for trimming catmint plants. 

What is catmint

Catmint (Nepeta x faassenii) is one of my favorite herbaceous perennials as it has excellent drought tolerance, attracts bees and butterflies, is extremely long flowering, is resistant to pests and diseases, and thrives even in colder hardiness zones (USDA Hardiness zones 3 to 8). Plus the lavender blue flowers add cottage garden appeal to the landscape. It’s also the most common type of catmint sold at garden centres.

This popular perennial plant, which is related to catnip (Nepeta cataria) and sometimes classified as an herb, is often used at the front of a flower border, along pathways, on awkward slopes, in rock gardens, or as a ground cover. The plants have silvery green leaves which provide the perfect foil for the cool hued blooms and, depending on the cultivar, range from about 9 inches to 3 feet tall. They also spread from about a foot to 3 feet across. Below you’ll find more information on the different cultivars of catmint to help you select the best one for your garden.

There are other species of catmint, including Japanese catmint (Nepeta subsessilis) and eastern catmint (Nepeta racemosa). These also respond well to early spring pruning and a shearing back after they flower in early summer. 

Why you need to know when to cut back catmint

Catmint is very easy to grow, but an occasional haircut is the best way to promote non-stop bloom and keep the plants – and the garden – looking tidy. It also allows you to start your catmint off strong in the spring, stimulates bushier growth (less sprawling), and reduces the occurrence of fungal diseases like powdery mildew. 

When to cut back catmint: 3 easy options

To be clear, you don’t have to prune back catmint, but for the best show of blooms and lots of fresh foliage, it’s a good idea to do so occasionally. Here are 3 options for when to cut back catmint.

When to cut back catmint: Option 1

In late winter or very early spring (February to April, depending on your location) I go out to the garden with my hand pruners, ideally my Felco #2’s, to clean up my catmint plants. The grey-green foliage emerges early, popping up in the center of the plant. However, the dead foliage from the previous season still surrounds that fresh healthy growth. Using your hand pruners, remove the dead stems, cutting them back to an inch or two away from the new growth. 

If you prefer, you can cut back the dead growth on catmint in late autumn. Trim the entire plant back to 4 to 6 inches above the ground. I prefer to prune in spring, however, because leaving the dead plant material in the garden over winter insulates the crown of the plant. It also provides shelter and protection to overwintering bees, butterflies, and other types of insects. 

If your catmint frequently gets powdery mildew in mid to late summer, a fall or spring cleanup of old branches removes spores and boosts air circulation around the plant. This minimizes the reoccurrence of fungal diseases. 

When to cut back catmint: Option 2

The next pruning time is in early summer just after the initial heavy blooming period has finished. This trim promotes compact, neat growth and a second flush of blooms that continues for months. In my zone 6 garden this takes place in early July. Removing the spent flowers and cutting the whole plant back by half is a technique called the ‘Chelsea Chop’.  I use hedge clippers or hand pruners to cut the plants back. Hedge clippers are the faster method and catmint plants are very forgiving. You don’t have to be extremely precise when trimming the plants. 

When to cut back catmint: Option 3

The final choice for when to cut back catmint is to clean up branches or wayward growth during the growing season. For example, larger catmint varieties tend to flop onto beds and pathways when they’re top-heavy with blooms. Don’t be shy about cleaning up the plants as needed. They’ll respond with new foliage and new flowers. As well, there are times that I spot a few dead stems on my summer catmint plants. A quick trim with my garden shears removes brown branches and keeps the plant tidy. 

Types of catmint

When you head to your local nursery you’ll see there are a lot of choices for catmint lovers. There is a range of plant sizes and forms, as well as bloom colors so do a little research before you shop.

• Walker’s Low – Among the most widely grown catmint cultivars, Walker’s Low is ironically one of the taller growing options. The vigorous plants grow 30 inches tall and about 36 inches wide with one foot flower spikes. With its sprawling habit, it’s the perfect perennial for planting alongside a pathway or at the front of a garden bed.
• Six Hills Giant – Another stunner, Six Hills Giant is a classic cultivar that has the same width and height as Walker’s Low. It happily flowers from early June through late September, and sometimes even later. The showy lavender-blue flowers are beloved by bees and butterflies. 
• Cat’s Meow – If you want a catmint with tidier growth try Cat’s Meow. This small stature plant boasts upright growth that forms a neat mound in the garden. Expect each plant to grow 1 1/2 feet tall and 2 feet wide. 
• Cat’s Pajamas – If Cat’s Meow isn’t compact enough for you, Cat’s Pajamas is even smaller! It grows just 9 to 12 inches tall and is ideal as a long-flowering edging plant. The vibrant purple flowers are produced all along the stem giving the appearance of just flowers – no leaves. And it starts to bloom very early in the season.

More tips on growing great catmint

To help you enjoy the longest flowering period and disease-free foliage, here are more tips for growing catmint. 

• Location – Planting a catmint plant in the right site goes a long way to promoting healthy growth. Look for a garden bed that offers a sunny position and well-draining soil. Avoid spots with soggy soil. In Southern climates, partial shade in the afternoon offers relief from summer heat. I work compost into the soil at planting time as well as an organic flowering plant fertilizer. 
• Watering – As noted above, catmint is drought tolerant and can withstand occasional dry spells. That said it is important to water during the initial growing season to help the plant settle in. If there has been no rain, water deeply once a week from planting until the ground freezes. I don’t water established catmint plants. 

For more information on growing perennial plants, be sure to read these articles:

• The longest flowering perennials to plant in your garden
• Bigroot geranium: A grow guide
• When to cut back bee balm
• How and when to trim back iris plants