Catmint — A “Must-Have” Perennial

  • By Pat Chadwick
  • /
  • April 2015 – Vol 1. No. 4

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 to three 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 impressive four to six 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.

The Haven volunteers and I are busy doing winter pruning. I’m often asked about pruning by garden visitors: what to prune, when to do it, and how much to cut back. We prune most of our plants fairly hard to stimulate as much new growth as possible since new growth often produces more flowers. After all, making flowers to feed the bees is what we’re all about!

We perform this task every year in late January and into early February. We delay pruning until then to provide forage and cover for the many birds that use the Haven and to ensure that any frost damage is confined to the outer part of the plant. Here’s how we prune different types of plants at the Haven.

Herbaceous perennials

These plants are typically cut back to the base, although in the case of plants like milkweed that are late to re-sprout, it can be helpful to leave visible stems so you’ll remember where the plant is located. Some examples from the Haven:

The first photo shows calamint, Calamintha nepetoides, just before pruning. You can clearly see last year’s dead flower stalks with this year’s new growth at the base. Cut the old stalk down to the top of the new growth.

The next picture is sedum ‘Autumn Joy’, Hylotelephium ‘Autumn Joy’ just after pruning. Isn’t the new growth cute? It looks like tiny heads of lettuce! I prune this plant earlier — in late fall or early winter — as the hollow stems make great overwintering sites for beneficial insects like ladybird beetles.

The final example is ‘Walker’s Low’ catmint, Nepeta x faassenii ‘Walker’s Low’. No need to be gentle with this plant; we prune ours with electric hedge trimmers. The photos show the same patch of plants before and after pruning. Calamint before pruning. Note the new growth at the base of the plant. Sedum ‘Autumn Joy’ showing new growth at the base Catmint ‘Walker’s Low’ before pruning Catmint ‘Walker’s Low’ after pruning

Woody perennials

Many woody perennials can be cut back hard to increase bloom. Two that are excellent candidates for this are the sages (Salvia spp.) and California fuchsia, Epilobium canum. Trim sages back to 6 to 12 inch stems to stimulate new growth at the base that will produce copious flowers from the following spring through fall.

California fuchsia is a great bee garden plant that provides nectar in late summer and fall when there are often few other nectar sources. It does tend to spread, and pruning a large patch by hand can be time-consuming. Run a lawn mower over it …. it will look terrible when you’re finished but the reward will be ample flowers the next year.

Salvia ‘Fire Dancer’ after pruning Salvia ‘Fire Dancer’ in full bloom

Epilobium ‘Catalina’ after pruning. This plant can be pruned with hedge shears or a lawnmower. Really! Epilobium ‘Catalina’ in full bloom

Woody shrubs that bloom on new growth

Some woody plants are pruned more like herbaceous perennials because they bloom on new growth. If they’re not pruned hard there will be little in the way of flowers next year. The example here is bluebeard, Caryopteris x clandonensis; stems are trimmed to 6 to 12 inches in length just above a node where new growth is emerging. It doesn’t look like much in the winter after it’s pruned, but it returns beautifully once spring comes and flowers nicely all summer and fall. Another common bee garden plant that needs to be trimmed this way is Russian sage, Perovskia atriplicifolia. Bluebeard after pruning Bluebeard in full bloom in July

Renewal pruning

Many woody shrubs can be cut back hard for renewal. Plants that have excessive dieback or that tend to get woody and unproductive with time are great candidates for this.

The first example is ‘Valley Violet’ ceanothus. This plant showed quite a bit of dieback by last fall. It was pruned hard (its size was reduced by about 2/3); the first photo shows how nicely it is growing back. We won’t get much bloom this year, but by next winter it will be covered with nutritious flowers for our bees.

Another candidate for this treatment is coyote brush, Baccharis pilularis; ours is the cultivar ‘Twin Peaks’. Over time this plant tends to accumulate a lot of woody stems that don’t produce flowers. We cut this back in the fall to the pile of sticks shown in the first photo; look at how nicely it comes back by spring.

This guide from UC Cooperative Extension has more information about tree and shrub pruning.

Ceanothus ‘Valley Violet’ after hard pruning Ceanothus ‘Valley Violet’ in full bloom in March

Coyote bush after very hard pruning Coyote bush regrowth after pruning

Grasses

We have native bunchgrasses in the Haven, which are sometimes used by bumble bees for nesting. They can nest at the base of the plant itself or in the ground immediately around the plant. We grow California fescue ‘Phil’s Silver’ (Festuca californica ‘Phil’s Silver) and deergrass (Muhlenbergia rigens) at the Haven. Neither is pruned in late winter, but for the sake of being thorough I’ve included them. We prune the fescue in early summer (around the time it goes dormant) to prevent excessive re-seeding. Deergrass is pruned every other year in fall, which provides sufficient time for new growth to develop by spring. As you can see from the photos, neither is particularly attractive after it’s cut back.

Pruning is not essential for maintenance of these plants, but it does provide a neater appearance in the landscape. To be safe, check for the presence of nests at the base of these plants before pruning. California fescue before pruning California fescue after pruning

Deer grass before pruning Deer grass after pruning

Fruit tree pruning

We also prune our orchard during the winter. This is especially important for us during the next few years as our young (planted in 2016-2017) trees develop their shape. As shown in the before and after pictures, the goal at this time is to develop a bowl shape with an open center. Prune off any branches that come out from the main trunk at very shallow or steep angles….ideally branches should be between 40 to 60 degrees off the main stem. Anything else tends to be weak and may snap under the weight of a load of fruit. For the same reason, aim for balance around the trunk: you can see that I’ve left three equally spaced branches at each node. I’ll likely remove the lower set of branches during next year’s pruning; for now their foliage provides valuable photosynthesis to help this young tree grow.

For more information about fruit tree pruning, check out this information from UC Cooperative Extension.

Pluot ‘Geo Pride’ before pruning. This tree was planted one year ago; it’s important to shape fruit trees early in their life for proper growth form. Pluot ‘Geo Pride’ after pruning. Remove branches growing into the center.

Dead branches

Dead branches should be pruned immediately, regardless of the time of year. There’s also no need to use wound dressing, as correct pruning cuts are done so that regenerative tissue remains on the plant and it heals itself.

Dieback on ‘Lutsko’s Pink’ manzanita. Remove dead branches as soon as they are observed. Manzanita ‘Sentinel’ showing a properly healed pruning cut

Plant of the Week: Walker’s Low Catmint

The University of Arkansas System Division of Agriculture does not promote, support or recommend plants featured in “Plant of the Week.” Please consult your local Extension office for plants suitable for your region.

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Walker’s Low Catmint
Latin: Nepeta x faassenii

Walker’s Low Catmint comes close to being the perfect perennial.

Plant people are fond of creating “best” lists of plants in an attempt to simplify the choices for gardeners looking for clarity in the oftentimes confusing plant world. That there is little agreement on what the best plants are is beside the point. At least we try. Today let’s consider the best – like I mean really the very best – perennial, Walker’s Low Catmint (Nepeta x fassenii ‘Walker’s Low’).

When in flower, this member of the mint family reaches about 18 inches tall with a spread to 2 feet across. Out of flower the foliage forms, a compact mound about 8 inches tall. Being a mint, the leaves are evergreen to about 15 degrees, opposite, about 2 inches long, gray-green and fragrant when crushed. It doesn’t produce pesky underground rhizomes like some mints but grows from a slowly expanding central crown.

Though called catmint, cats aren’t attracted to this plant like the true catnip, N. cataria. Deer and rabbits don’t care much for it either.

The flowers are what make catmint a real standout. They appear in midspring and continue to be produced through most of the growing season, although late spring and early summer is their showiest time. The lavender-blue flowers are produced on upright spikes held above the foliage that reach about 8 inches long. Individual flowers are small but produced in large numbers up the spike. Because the plant is a sterile hybrid and doesn’t set seed, it just keeps blooming in a vain attempt to procreate.

This plant is apparently an accidental hybrid between N. racemosa and N. nepetella that occurred in the lower part of Mrs. Walker’s garden in Ireland. Mrs. Patricia Taylor spotted its potential and took cuttings in the 1970’s. Four Seasons Nursery in Norwich, England, finally introduced it to the trade in 1988. The first hybrids of these two species were made by Dutch nurseryman J. H. Faassen in the 1930s, so the hybrid genus is named in his honor.

Walker’s Low, named for the garden – not the plant size, is a favorite amongst garden designers because its long bloom period makes it the ideal filler plant in the mixed perennial border. Plants tucked here and there in the front of the border provide unity to the design and lots of color over much of the growing season. It’s also ideal for edging walkways or use as a groundcover. It also can be used in containers, even containers that remain outside over winter.

And it’s tough – really tough. The Perennial Plant Association agrees about its toughness and wide adaptation so the association selected it as the 2007 perennial of the year. It’s adapted from zones 4 through 7.

Catmint should be grown in sunny, well-drained sites in a good garden soil. Wet wintertime conditions could finish it off. It grows in the shade but expect few flowers. Once established, it has great drought tolerance. It responds well to fertilization and will remain in bloom longer with good fertility levels. Cutting off the spent bloom spikes keeps the plants tidy and may help spur more flowers.

This plant has no serious pests, but after four or five years in one site it tends to look a bit shopworn. Dig and divide the plant in early spring and incorporate compost into the soil if plants are to go back in the same area. Propagation is by division or cuttings.

By: Gerald Klingaman, retired
Extension Horticulturist – Ornamentals
Extension News – July 27, 2007

The University of Arkansas Division of Agriculture does not maintain lists of retail outlets where these plants can be purchased. Please check your local nursery or other retail outlets to ask about the availability of these plants for your growing area.

‘Walker’s Low’ catmint flowering among other perennials.

The Perennial Plant Association has selected Nepeta xfaassenii ‘Walker’s Low’ as their Plant of the Year 2007. This herbaceous perennial in the mint family (Lamiaceae) is hardy in zones 3-8. The common name for the genus Nepeta – catmint – comes from the attractiveness to cats of the aromatic volatiles released from the broken stems of some plants in this genus, especially catnip (N. cataria). This species is not particularly attractive to cats, though some may be interested in it (mine ignore it, but go crazy over the real ‘nip). This species is a hybrid of N. racemosa and N. nepetella and is named for Dutch nurseryman J.H. Faassen who developed the first hybrids. This cultivar was developed in England and is named for a garden there, not for the plant’s size.

‘Walker’s Low’ produces soft, blue-purple flowers.

‘Walker’s Low’ has aromatic, gray-green to silvery foliage and produces profuse soft lavender-blue flowers over a long period from early summer through fall. Bees, butterflies and hummingbirds are attracted to the flowers.

The oval leaves have scalloped edges.

The opposite leaves are 1-2″ long with scalloped edges. The plant has 2-3 foot stems, but because of its arching habit the clumps are only 1½ -2 feet high if not staked. This variety does not flop as much as some catmints. It tolerates hot summer temperatures and is fairly drought resistant once established.

Landscape Uses

Catmints combine well with yellow flowers and foliage.

Nepeta xfaassenii ‘Walker’s Low’ has a clean-cut look and provides a good show of color nearly all summer, making it a good choice for the front of a border. It is also useful as a tall edging and in herb gardens. It can be used as a ground cover, cascading over walls, or in containers. It is very effective planted in large masses or drifts. Catmint combines well with roses, beebalm, Shasta daisies, and ornamental grasses with blue foliage. The flowers make a nice contrast to bright orange tulips and daylilies, and harmonize well with soft yellow flowers, such as, yellow foxglove (Digitalis grandiflora), Coreopsis ‘Moonbeam’ and lemon yellow daylilies such as ‘Bitsy,’ ‘Hyperion’ or many other cultivars. I have some planted in front of a Tiger Eyes™ cut-leaf sumac (Rhus typhina Tiger Eyes™) that has yellow foliage for most of the summer, then turns bright orange in fall, making an excellent contrast to the gray-green foliage and blue flowers.

Culture

Other cultivars of catmint grow taller than ‘Walker’s Low’.

Catmint grows well in full sun and any well-drained soil, although it will tolerate light shade. Once established it tolerates drought (but grows better when well-watered). Shear the plant back in spring for more compact habit. Cutting back plants by half to a third after the initial flush of flowers fade will promote reblooming and a more attractive appearance later it the season. ‘

Walker’s Low’ is supposedly sterile and therefore will not set seed, but I have had seedlings in my garden. The best method of propagation is by division in spring or from soft wood cuttings taken in summer (June and July). Non-flowering side shoots about 3 inches long should root in about 4 weeks.

Catmint has few pest problems and is not bothered by deer or rabbits. Maintain proper plant spacing to reduce problems with powdery mildew.

Some cultivars have white flowers.

In addition to ‘Walker’s Low’, there are many other cultivars of N. xfaassenii, including:

  • ‘Blue Wonder’ has lavender-blue flowers
  • ‘Dawn to Dusk’ produces pink flowers
  • ‘Dropmore’ – Dark blue flowers
  • ‘Six Hills Giant’ – Violet-blue flowers
  • ‘Snowflake’ has white flowers
  • ‘White Wonder’ is another cultivar with white flowers

– Susan Mahr, University of Wisconsin – Madison


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