Walker’s Low Catmint (Nepeta x faassenii ‘Walker’s Low’) is a popular perennial plant known for its aromatic gray-green foliage and beautiful spikes of blue-purple flowers. This compact mounding plant has graced many home gardens thanks to its long bloom time, drought tolerance and appeal to pollinators.
However, some gardeners have questioned whether Walker’s Low Catmint has the potential to become invasive Invasive plants are non-native species that spread aggressively, displacing native plants and disrupting local ecosystems
Understanding the growth habits and reproductive mechanisms of any plant is key to determining its invasive potential In this article, we’ll take an in-depth look at Walker’s Low Catmint to find out if gardeners should be concerned about it behaving invasively.
What Makes a Plant Invasive?
Before deciding if Walker’s Low Catmint is invasive, it’s important to understand what makes a plant invasive in the first place. In general, invasive plants share the following traits:
- They are non-native species introduced from another region.
- They spread rapidly through seeds, roots, or plant fragments.
- They establish quickly in new areas.
- They grow and reproduce prolifically.
- They adapt to a wide range of conditions.
- They outcompete native plants.
- They lack natural controls like pests or diseases to limit their growth.
Plants with these attributes can dominate habitats, reduce biodiversity, disrupt food webs, and cause major ecological damage. Not all non-native plants become invasive, but those with aggressive growth and reproduction pose the biggest threat.
Is Walker’s Low Catmint Native?
Walker’s Low Catmint originated as a hybrid between two catmint species from Europe and the Mediterranean – Nepeta faassenii and Nepeta racemosa. It was bred in England in the late 1930s and is not native to North America.
The fact that Walker’s Low Catmint comes from another region raises its potential to exhibit invasive behavior. Many invasive plants are introduced species that flourish outside their native range. However, non-nativeness alone doesn’t guarantee invasiveness. The specific growth habits of the plant provide more clues about its potential to spread aggressively.
Growth Habits of Walker’s Low Catmint
One major factor influencing invasiveness is a plant’s growth rate and habits. Rapid growers that create dense thickets tend to be the most invasive.
Walker’s Low Catmint has a relatively moderate, clumping growth habit. It reaches a modest size of 18-24 inches tall and wide. The plants grow at a moderate pace, not nearly as quick as aggressive invaders like kudzu or purple loosestrife.
The compact, mounding form means Walker’s Low Catmint doesn’t run rampant through above-ground stems or roots. It tends to stay put where planted, expanding slowly compared to highly invasive mints. These conservative growth habits make it less likely to spread out of control.
Reproductive Mechanisms
Another key factor is how prolifically and efficiently a plant can reproduce. Prolific seed production, rhizome growth, and plant fragmentation enable invasive plants to colonize new areas rapidly.
Walker’s Low Catmint can spread through self-sown seeds. However, it does not produce the extremely large volumes of seeds that enable heavy colonization. Its seeds are relatively short-lived and do not accumulate in the soil seed bank.
Walker’s Low Catmint also lacks the vigorous rhizomes of notoriously invasive mints. It does not readily propagate from fragments, and its slower growth curbs vegetative spread. Overall, its reproductive capacity is modest compared to aggressively invasive plants.
Environmental Tolerance and Competitive Ability
Invasive plants can thrive in a broad range of conditions, outcompete natives, and flourish without natural controls.
Walker’s Low Catmint does tolerate drought, heat, and poor soils. However, it does not exhibit rampant competitive ability to choke out intact native plant communities. It may compete decently in disturbed areas against other non-natives but does not pose a major threat to stable natural ecosystems.
Susceptibility to Natural Controls
In their native ranges, plants are often kept in check by diseases, pests, and herbivores that have evolved alongside them. Introduced plants may escape these natural controls, fueling invasive spread.
Walker’s Low Catmint lacks major specialized pests in North America. It can suffer from mint rust disease but has no major insect enemies. The absence of natural controls enables it to grow freely. However, its moderate growth temper its potential to become rampantly invasive.
Is Walker’s Low Catmint Considered Invasive?
Based on analysis of its specific traits, most experts agree Walker’s Low Catmint has low invasive potential. While it can spread through seeds into neighboring areas, it lacks aggressive growth and reproduction to invade intact plant communities.
No major institution has designated Walker’s Low Catmint as an invasive species. It has been grown extensively with no major reports of invasive behavior. However, gardeners should always monitor and properly maintain plants to prevent spread.
Growing Walker’s Low Catmint in a Garden Setting
When grown responsibly, Walker’s Low Catmint makes a beautiful garden plant. Here are tips for growing it without invasiveness:
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Plant in contained beds instead of near open natural areas.
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Deadhead spent flowers to reduce self-sowing.
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Pull out unwanted self-sown seedlings.
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Surround with low-growing perennials that act as a living mulch.
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Monitor for and remove any spread beyond its intended planting area.
Walker’s Low Catmint exhibits low invasive tendencies and poses little risk of aggressive spread when properly managed. Its moderate growth, limited reproduction, and lack of running roots or stems make it unlikely to colonize natural areas. While no plant can be guaranteed 100% non-invasive, this beloved garden perennial has demonstrated itself to be well-behaved. With mindful planting and maintenance, gardeners can safely enjoy the beauty and pollinator appeal of Walker’s Low Catmint.
How to Grow Walker’s Low Catmint
- Location: Walker’s Low catmint prefers full sun (some afternoon shade is okay) and sandy or loamy, well-draining soil. It will tolerate most soil types, including clay. Catmint will not tolerate wet, soggy, poorly draining soil and will develop root rot. If you are looking for a flowering perennial for a sunny, wet location, try swamp milkweed (Asclepias incarnata) instead.
- Planting: Plant Walker’s Low catmint in the spring or fall; space plants 18 to 24 inches apart to allow for proper air circulation.
- Watering: Water newly planted catmint regularly to help establish the roots. Once established, catmint is drought-tolerant (for watering guidance, see “How to Water Your Plants”).
- Mulch: Apply a layer of mulch around catmint to conserve moisture and suppress weeds.
- Fertilizer: Catmint does not require supplemental fertilization. A thin layer of compost (either homemade or store-bought) applied in the early spring will enrich the soil structure, improve drainage and support plant health.
- Pruning: After the first flush of spring flowers, use sharp pruning shears to cut back the entire plant by about one-third to promote reblooming and bushier growth.
- Pests and Diseases: Catmint is relatively resistant to pests and diseases; aphids or spider mites can cause occasional problems. Overwatering and wet, soggy soils are the most frequent causes of problems with catmint, causing plants to develop root rot.
The small, tubular flowers of Walker’s Low catmint are arranged in spiky clusters. courtesy of Walters Gardens, Inc.
Do You Cut Back Walker’s Low Catmint?
Yes – cutting back, pruning, deadheading, and dividing Walkers Low catmint can help maintain the plant’s vigor and appearance. Walker’s Low Catmint is not an evergreen plant; it is deciduous, and can benefit from being cut back and deadheaded during the growing season to keep a tidy appearance.
- Cutting Back/Pruning: When the first flush of spring flowers begin to fade, give catmint a light shearing or pruning and cut back the entire plant by about one-third. This will stimulate new growth and encourage a second round of blooming.
- Deadheading: Regularly remove spent flowers by deadheading. This process involves cutting or pinching off the faded blooms. Deadheading prevents the plant from setting seed, redirecting its energy toward producing new flowers.
- Dividing: Every few years, consider dividing mature catmint plants. This helps to rejuvenate the plant, preventing the center of the plant from become woody and promoting increased flowering. Divide the plant in early spring or fall.
Walker’s Low Catmint – Nepeta x faassenii
FAQ
Does Walker’s low catmint spread?
Yes, Walker’s Low catmint (Nepeta x faassenii ‘Walker’s Low’) does spread, but it’s not considered invasive. It tends to grow in a clump-forming, spreading manner, rather than aggressively spreading like some other plants in the mint family.
What are the disadvantages of catmint?
Is Walkers Low catmint invasive?
In addition to its non-invasive nature, Walker’s Low Catmint is a low-maintenance, drought-tolerant plant that thrives in sunny locations with well-drained soil.
Will catmint take over my garden?
While not truly invasive, catmint (Nepeta) can spread and potentially become a bit unruly in a garden, especially if not regularly pruned or managed.
Is Walker’s low catmint invasive?
It was bred in England in the late 1930s as a hybrid between Nepeta faassenii (Faassen’s catmint) and Nepeta racemosa (racemed catmint), both of which originated from southern Europe. Since Walker’s Low Catmint is not native to the United States or Canada, any propagation beyond intentional garden planting could be considered invasive spread.
Is Walker’s low catmint a perennial?
Walker’s Low Catmint (Nepeta x faassenii ‘Walker’s Low’) is an herbaceous perennial in the mint family that has become a staple in many home gardens. With its aromatic gray-green foliage and stunning indigo-blue flower spikes that bloom from late spring to fall, it’s easy to see why this plant is so beloved.
Is Walker’s low catmint a weed?
Walker’s Low Catmint does have some weedy qualities – it is tolerant of drought, heat, humidity, and poor soils. However, it does not exhibit the extremely vigorous competitive ability of notorious invasives. The plant spreads slowly into open space, but does not aggressively choke out intact native plant communities.
Is Walker’s low catmint native to North America?
Walker’s Low Catmint is not a native North American species. It was bred in England in the late 1930s as a hybrid between Nepeta faassenii (Faassen’s catmint) and Nepeta racemosa (racemed catmint), both of which originated from southern Europe.
How fast does Walker’s low catmint grow?
It reaches a mature size of 18-24 inches tall and 24-30 inches wide. The plant grows at a moderate rate, not nearly as quick as highly invasive plants like Japanese knotweed or purple loosestrife. The compact, clumping form of Walker’s Low Catmint means it does not typically spread out aggressively through above-ground runners.