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 aren’t sure if Walker’s Low Catmint could become an invasive species. Invasive species are non-native species that spread quickly, pushing out native plants and upsetting 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?
There are some things you should know about invasive plants before you decide if Walker’s Low Catmint is one of them. 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.
These kinds of plants can take over habitats, lower biodiversity, mess up food webs, and do a lot of damage to the environment. Not all non-native plants become invasive, but the ones that grow and reproduce quickly are the most dangerous.
Is Walker’s Low Catmint Native?
Walker’s Low Catmint is a cross between two species of catmint that come from Europe and the Mediterranean: Nepeta faassenii and Nepeta racemosa. It is not from North America; it was bred in England in the late 1930s.
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
- Walker’s Low catmint grows best in sandy or loamy, well-drained soil that gets full sun (some afternoon shade is fine). It will tolerate most soil types, including clay. Catmint can’t grow in soggy, wet soil that doesn’t drain well; it will get root rot. Try swamp milkweed (Asclepias incarnata) instead if you want a flowering perennial that will do well in a sunny, wet spot.
- Plant Walker’s Low catmint in the spring or fall, making sure to leave 18 to 24 inches between plants to let air flow.
- Watering: Give newly planted catmint regular watering to help the roots grow. Once it’s established, catmint can handle not getting enough water (see “How to Water Your Plants” for tips).
- Mulch: Put a layer of mulch around catmint to keep the soil moist and keep weeds from growing.
- Fertilizer: Catmint does not require supplemental fertilization. Adding a thin layer of compost (either your own or store-bought) in the early spring will improve the soil’s structure, let more water drain away, and help plants stay healthy.
- Pruning: Once the first flowers appear in the spring, cut back the whole plant by about a third with sharp pruning shears. This will encourage more flowers and bushier growth.
- Pests and Diseases: Catmint isn’t too easily hurt by pests and diseases, but aphids and spider mites can sometimes be a problem. Most problems with catmint are caused by too much water and soggy, wet soils. This makes plants get 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.
- Catmint should be lightly sheared or pruned and the whole plant should be cut back by about a third when the first flowers of spring start to fade. As a result, the plant will grow new leaves and flowers again.
- Deadheading: Regularly remove spent flowers by deadheading. This process involves cutting or pinching off the faded blooms. By cutting off the spent flowers, you stop the plant from going to seed and direct its energy toward making new flowers.
- Dividing: Every few years, consider dividing mature catmint plants. That helps the plant get stronger, keeps the middle of the plant from turning woody, and makes more flowers grow. 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?
While generally low-maintenance, catmint does have a few potential downsides. It can become floppy and sprawl, especially if it’s in rich soil or not pruned regularly. Additionally, some types can easily self-seed and spread, which might not be ideal in a small garden.
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?
Catmint (Nepeta) is not really invasive, but it can spread and get out of hand in a garden if it is not regularly trimmed 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?
You can find Walker’s Low Catmint (Nepeta x faassenii ‘Walker’s Low’) in many home gardens. It is a perennial herbaceous plant in the mint family. 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.