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Catmint — A

Catmint — A "Must-Have" Perennial

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Catmint 'Walker's Low'

If you're looking for a perennial that is long blooming, heat tolerant, resistant to pests and diseases, and easy to grow, then allow me to recommend catmint (or Nepeta) to you. After years of experimenting with drought-tolerant and deer-resistant plantings, I still include this top performer on my list of "must have" plants. It plays a prominent role in my ornamental garden and provides interest in all four seasons. It has attractive gray-green foliage that emerges in neat, tidy mounds in April. By May, the plant fairly explodes with a profuse haze of soft lavender-blue flowers. After the initial flush of blossoms, the plant continues to show lots of color well into late summer or early fall. Colorful calyces that are similar in color to the blossoms enhance the floral display even after the blossoms are gone. Left standing over the winter months, the foliage fades to a pleasing soft silvery gray color.

Emerging Catmint Foliage

This herbaceous perennial is a member of the mint family (Lamiaceae), which includes lavender, rosemary, thyme, bee balm and giant hyssop. In addition to having aromatic leaves, these plants share other common traits, such as two-lipped flowers, square stems and opposite leaves. Many people confuse catmint with catnip (Nepeta cataria). While the two are closely related, catnip is more aromatic than catmint but has less ornamental value.

Catmint plays well with others. If you love the classic combination of lavender and roses but find lavender too finicky to grow in this area, catmint is a good substitute. Just like lavender, catmint can be used to cover the bare "limbs" of rose bushes. It's cool-toned foliage and flowers offer a pleasing counterpoint to the vivid tones of the roses.

Catmint blends well with most other colors but looks particularly appealing when paired with colors in the red-blue color spectrum. In my own garden, it looks stunning planted with irises. In particular, it pairs well with the medium lavender-blue iris 'Crater Lake' and with the blue-violet hues of iris 'Swingtown.' The mounded shape contrasts nicely with the vertical silhouettes and deeper lavender shades of Allium cultivars 'Gladiator,' 'Giganteum,' or 'Purple Sensation.' As spring merges into summer, catmint harmonizes well with the cascading burgundy foliage of 'Garnet' Japanese Maple or with the purple foliage of Heuchera 'Plum Pudding.' 'Purple Ruffles' basil is yet another terrific companion for catmint, plus it's edible! Yellow-flowering plants such as Hemerocallis 'Happy Returns,' Achillea 'Coronation Gold,' or Coreopsis 'Early Sunrise' also make a pleasing combination with catmint.

The most popular catmint cultivars grown commercially in this country belong to the hybrid Nepeta x faassenii. The plants are named for J. H. Faassen, a Dutch nurseryman, in whose nursery this hybrid first appeared. The flowers of N. x Faassenii are sterile and do not need to be deadheaded to prevent self-sowing.

Whereas members of the N. X faassenii family are sterile, other related species, such as the following, are fertile and may need to be deadheaded to prevent reseeding:

Siberian catmint (N. sibirica) – Tall (two tothree feet) upright plant with large green leaves and rich blue flowers.
Japanese catmint (N. subsessilis) – Unlike the other varieties of catmint, this one prefers moist soil. Although it will take full sun, it likes partial shade.
Yellow catmint (N. govaniana) – Native to the Himalayas, this hard-to-find variety has yellow flowers which bloom later in the summer.
Veined Nepeta (N. nervosa) – Native to India, this species grows one to two feet tall and is characterized by strong veins on three- to four-inch long leaves.
Greek catmint (N. parnassica) – This catmint, which is more commonly found in European gardens than here in this country, grows to an impressivefour tosix feet tall and wide.

In a comparative study of catmints conducted by the Chicago Botanic Garden between 1999 and 2006, 36 catmints were evaluated with the goal of identifying outstanding specimens in terms of their ornamental traits, disease and pest resistance, cultural adaptability, and winter hardiness (the botanical garden is located in zone 5b). Of 22 catmints that were highly rated, the following four top performers received five-star excellent ratings based on their heavy flower production over a protracted bloom period:

'Joanna Reed' – Lavender-blue flowers on 24-inch tall by 48-inch wide plants. It is named for the late Pennsylvania gardener who discovered it.
'Six Hills Giant' – Lavender-blue flowers on 30-inch tall by 48-inch wide plants.
'Select Blue' – Lavender flowers on 14-inch tall by 30-inch wide plants.
'Walker's Low' – Lavender-blue flowers on 30-inch tall by 36-inch wide plants. As an aside, the name comes from a garden in Ireland and not because it is short. In fact, it is nearly as tall as 'Six Hills Giant.' In 2007, the Perennial Plant Association selected 'Walker's Low' as their Perennial of the Year.

If you're compelled to look for catmint in the local garden centers, don't limit yourself to just these four selections. Many other excellent cultivars are available, such as 'Dropmore,' 'Blue Wonder,' and 'Junior Walker,' which, at 16 inches tall, is a shorter version of 'Walker's Low.'

HOW TO CARE FOR CATMINT

Give catmint plenty of space as it tends to grow wider than tall.
Although it prefers full sun, catmint will thrive with some afternoon shade.
Keep new plants or transplants watered until they can fend for themselves. After that, established plantings are drought and heat tolerant.
Don't bother to fertilize it. Catmint prefers well-drained soil that is not overly fertile. In fact, soil that is too rich may cause the plant to flop over or split in the middle. Should that happen, shear the plant back to tidy it up. Some compost in fall or spring will provide sufficient nutrients to keep the plant happy.
Shear the plants back by a third or more after their first flush of bloom is past. This will neaten the plants, contain their size, and encourage a second flush of blooms later in the summer. Even without being sheared, the plant will repeat bloom and continue to look attractive over the hot summer months.
Leave spent foliage in place over winter to help protect the crown. Wait until early spring to cut it back.
To keep catmint vigorous, divide it every three to four years in either spring or early fall. Keep it well watered the first growing season until the plants become established.
Some cultivars of catmint can grow quite large. If you want to contain the overall size of the plant, pinch it back in spring after it is a few inches tall to promote a bushier growth habit.

HOW TO PROPAGATE CATMINT

To propagate catmint, slice off a vertical section of an established clump in spring. Make sure the division has several young shoots and a substantial root system. Keep well watered until the plant becomes established.
Catmint may also be propagated through cuttings. Take three-inch long cuttings of healthy shoots in the spring before flower buds form. Insert the cuttings into a moist medium such as sand or a peat-perlite mix. They should root within two or three weeks.

PESTS, POLLINATORS, AND OTHER CONSIDERATIONS

With regard to pests and diseases, catmint is generally untroubled by either. Leaf spot is the only problem that occasionally occurs. This fungal disease is not considered serious enough to warrant control practices.
As I have learned from experience, some cats are attracted to catmint. If this is a concern for you, place chicken wire over newly planted or transplanted catmint to prevent kitty from eating or rolling around in it.
This plant is a veritable bee and butterfly magnet. As a bonus, hummingbirds love it as well.
If four-footed critters other than cats are a problem in your garden, you'll love this plant.Its minty, aromatic foliage repels rabbits, voles, and deer. Now THIS is a plant that earns its keep!

RESOURCES

Armitage, Allan M., "Herbaceous Perennial Plants," Third Edition, 2008.

Clausen, Ruth Rogers, "50 Beautiful Deer-Resistant Plants – The Prettiest Annuals, Perennials, Bulbs, and Shrubs that Deer Don't Eat," 2011.

"A-Z Encyclopedia of Garden Plants," published by The American Horticultural Society, editors-in-chief Christopher Brickell and H. Marc Cathey, 2004.

"A Comparative Study of Cultivated Catmints," Richard G. Hawke, Plant Evaluation Manager, Chicago Botanic Garden, https://www.chicagobotanic.org/downloads/planteval_notes/no29_catmint.pdf.