We’ve all fallen prey to the temptation of ‘perfect’ plants, only to discover years later that they’ve become a nuisance in our gardens. The promise of fast-growing, maintenance-free, or quick-spreading foliage can be deceiving, as some seemingly harmless plants turn out to be invasive aggressors. It’s astonishing how many familiar garden staples are actually troublemakers in disguise.
When adding a new plant to your space, it’s essential to approach with caution and arm yourself with knowledge about invasive species that can do more harm than good.
What are Aggressive and Invasive plants?
While not all non-native plant species are inherently problematic, some can exhibit invasive tendencies, outcompeting native varieties and growing rapidly out of control. Conversely, aggressive growers may multiply quickly but lack the ability to overwhelm your property or compete with native flora. Both types of plants can cause issues in your garden, and it’s essential to be aware of potentially troublesome species.
Many cities and towns maintain lists of invasive plants that you should avoid at all costs. It’s crucial to be mindful of these sneaky invaders as they may be sold at local garden centers without warning. However, not all impressive growers or easy-to-maintain plants will cause trouble. If in doubt, it’s always best to stick with native species and don’t hesitate to ask questions.
In the following list, we’ve gathered information on characteristics, growth habits, and other relevant details for each plant, providing valuable insights for gardeners seeking to avoid potential problems.
Vines
English Ivy
As European colonizers expanded their reach across the globe, they inadvertently introduced an invasive plant species that would go on to wreak havoc on ecosystems worldwide. This persistent evergreen vine, known as English ivy, has a few enticing qualities that have contributed to its widespread cultivation – it’s low-maintenance, tolerant of drought and low-light conditions, and even withstands harsh winters.
However, beneath its seemingly harmless exterior lies a plant with some rather insidious properties. For one, it has an alarming tendency to outcompete native flora, suffocating them under its dense foliage and rendering habitats inhospitable for certain wildlife. Furthermore, English ivy’s toxic nature poses a threat not only to humans but also to animals that venture too close. Its ability to cause skin irritation in some individuals only adds to the list of concerns.
When left unchecked, this invasive species can even inflict significant damage on buildings and infrastructure. In light of these drawbacks, it’s imperative to exercise caution when considering English ivy for your garden or landscape – there are far more environmentally friendly options waiting to be explored.
Japanese Honeysuckle
The Japanese honeysuckle is an invasive plant that originates from Japan. Characterized by its woody stems and vines that produce vibrant flowers in shades of pink, orange, and yellow during late spring and early summer, it’s often recommended for ornamental purposes due to its reliable blooming habit. However, this species poses significant problems as it can quickly overgrow young trees, forming a dense canopy that blocks light from reaching the trees below.
In fact, its unchecked growth can have devastating effects on native ecosystems. As such, it is generally advisable to avoid planting this invasive species. If you already have it on your property, it’s crucial to monitor its spread and prune it vigorously to prevent further harm.
Periwinkle
Periwinkle was first introduced to North America and Australia as an attractive ornamental option. Characterized by its evergreen vines adorned with vibrant purple flowers, this plant has gained popularity among nurseries. However, beneath its aesthetically pleasing exterior lies a concerning truth: periwinkle is a highly invasive species that can swiftly spread and form a dense ground cover, stifling all growth beneath it.
Furthermore, periwinkle requires minimal maintenance to survive, allowing it to rapidly colonize new areas. Unfortunately, this means that once established, periwinkle can be extremely difficult to eradicate. For these reasons, we strongly advise against using periwinkle as a ground cover and instead recommend alternative options like the glory vine.
Kudzu
Originally hailed as a decorative vine, kudzu has evolved into a formidable weed, wreaking havoc on unsuspecting landscapes. Its striking features include vibrant purple flowers and ornamental leaves. Despite its allure, nurseries often recommend it for its rapid growth, providing instant shade, privacy, or ground cover, as well as edible blossoms.
However, this invasive plant’s insatiable appetite for space has earned it the dubious distinction of being nearly impossible to control or eradicate. Its spread is nothing short of phenomenal, suffocating other plants and leaving a trail of destruction in its wake. In light of these facts, it’s wise to exercise extreme caution – or better yet, simply avoid kudzu altogether.
Chinese Wisteria
The American beauty, Wisteria, is a stunningly gorgeous invasive species that’s hard to resist. With its vibrant purple or pink flowering vines, it’s no wonder nurseries recommend it for ornamental purposes. However, beneath its charming exterior lies a problematic reality. Wisterias have a tendency to spread rapidly, outcompeting other species in the process. This can be particularly devastating in forested areas where they can even kill young trees.
In light of these concerns, if you’re in the U. S., consider planting American Wisteria as an alternative.
Edible Plants
Mint
Mint is a popular garden plant prized for its potent aroma and zesty flavor, making it an excellent addition to many culinary creations. Its appearance can vary depending on the specific variety, with some featuring compact, upright growth while others trail along the ground. Small, edible leaves are a characteristic feature of this herb. Despite its many charms, mint requires careful cultivation to prevent it from becoming too dominant in the garden.
Nurseries often recommend mint due to its versatility as a garnish and ingredient in various dishes. However, mint’s aggressive nature means it can quickly spread and overpower nearby plants if not kept in check. To maintain control, it’s essential to grow mint in a pot or separate container, ensuring this fragrant herb remains a welcome addition to your garden rather than an unwelcome invasive species.
Garlic mustard
Garlic mustard is an aggressive biennial species that’s often overlooked due to its unique characteristics. Despite having a pungent aroma reminiscent of horseradish rather than mustard, this edible plant has gained popularity among foragers and gardeners alike. The lilypad-shaped leaves and long taproot are distinctive features that set it apart from other edibles. Notably, nurseries recommend garlic mustard due to its hardiness and ability to thrive in a variety of conditions.
However, one must be cautious when handling the plant’s seeds as they have a tendency to scatter over long distances and can remain viable for extended periods. As such, foraging for wild garlic mustard rather than planting it is generally recommended, as it can be found growing freely in many areas.
Japanese mugwort
Mugwort is an invasive species with a dubious reputation originating from Europe or Asia. Although it may not be readily available at local nurseries, enthusiasts of medicinal herbs can find seeds online from sellers catering to this niche market. The plant itself has a herb-like appearance, bearing a striking resemblance to chrysanthemum. Its perennial nature makes it a tempting option for those seeking long-term benefits, as it returns year after year with minimal maintenance.
However, its propensity for spreading via rhizomes renders it notoriously difficult to eradicate, not to mention the potential for inducing allergic reactions. In light of these drawbacks, it is advisable to steer clear of Mugwort and instead opt for other, more tractable options when seeking herbal remedies.
Wintercress
Wintercress, a perennial belonging to the mustard family, bears a striking resemblance to its watercress cousin. Its invasive nature is particularly evident in Japan, where it has spread far and wide. The plant’s appearance is characterized by long stems adorned with delicate yellow blooms. While nurseries recommend wintercress for its bee-friendliness and lack of demanding growing conditions, the reality is that it often finds itself classified as a weed in many regions.
This unwanted guest tends to pop up almost anywhere, but fortunately, it is not overly troublesome to eradicate. Ultimately, while wintercress may not be the most egregious offender on this list, there are certainly more desirable options for those seeking edible plants with attractive flowers.
Purslane
Purslane is a hardy, edible succulent that has made its way from Southeast Asia to gardens around the world. Its chunky, rounded leaves allow it to thrive in a variety of conditions, making it a low-maintenance addition to any outdoor space. While nurseries tout purslane as a super easy-to-grow crop, its aggressive nature means that it can quickly take over an entire garden if left unchecked.
As a prolific producer of new plants, purslane has a tendency to choke out other crops and spread rapidly in any environment. Despite this, the succulent’s versatility in salads, sandwiches, and more makes it well worth the effort of containing its growth. When grown in a pot, purslane can be a delightful addition to many different types of dishes.
Claytonia
California State University Channel Islands recommends ‘miner’s lettuce’ as a low-maintenance and cold-hardy salad green that is rich in vitamin C. This easy-growing green forms green leaf clusters that grow in patches, making it a great option for those who want to add some extra nutrition to their salads without much fuss.
While nurseries often view miner’s lettuce as a weed, it can actually be a valuable addition to your garden – just be aware that it has a tendency to self-sow and may spread more than you intended. Overall, miner’s lettuce is a great choice for anyone looking to add some extra crunch and nutrition to their salads.
Trees
Norway maple
While many European maple species are admired for their unique characteristics, there’s one particular species that stands out for its pleasing growth habit. Like other maple trees, it boasts a classic silhouette and vibrant foliage. Nurseries often recommend this species due to its rapid growth rate and ability to thrive in challenging environments.
However, its quick growth can be a double-edged sword – it may overshadow and outcompete surrounding vegetation, reducing their access to essential sunlight. For these reasons, when selecting a maple for your yard, consider opting for a native species that’s better suited to local conditions.
Sycamore maple
The European and Asian maple species is known for its assertive nature, characterized by its striking appearance. Reaching heights of up to 60 feet, it bears an uncanny resemblance to other maple trees. Nurseries often recommend this variety due to its attractive foliage. However, this species has a less-than-desirable trait: it produces copious amounts of seeds that can rapidly overwhelm the surrounding area, potentially suffocating other plants.
In conclusion, if you’re considering planting a maple tree, opt for a native species in your region instead.
White poplar
The black poplar, a species brought to North America in the 1700s as an ornamental tree, is not without its problems. Its striking features include large leaves with white undersides that offer a beautiful display when the wind blows through. However, this tree’s aggressive nature means it can outcompete other trees, pushing them out of the ecosystem. As such, nurseries and horticulturists advise against planting this variety, instead recommending alternatives that are less invasive.
Princess tree
The empress tree, also known as royal paulownia, has been causing trouble in American gardens since its introduction from China in the 1840s. This invasive species is a fast-growing ornamental that can quickly outcompete native plants and trees, casting a shadow over their natural beauty. Its showy pinkish-purple flowers may be an attractive feature, but they’re not enough to outweigh the negative impact it has on local ecosystems.
With its tendency to produce numerous seeds that germinate easily and travel far distances, the empress tree is best avoided in favor of more environmentally friendly ornamental options.
Shrubs etc.
Japanese barberry
Native to Japan, the Japanese barberry was introduced to North America in the late 1800s as an ornamental plant. Its thorny shrub-like appearance is characterized by red berries and leaves. One of its most attractive qualities is its ability to thrive in shade and withstand drought without requiring excessive maintenance. Additionally, it’s not a magnet for pests. However, this very same adaptability that makes it appealing also allows it to outcompete native species for resources.
Furthermore, the plant provides a favorable environment for Lyme disease-carrying ticks, making it a less-than-ideal choice for gardeners seeking to minimize risk. Ultimately, there are many other attractive shrubs available that do not come with these drawbacks.
Common Mullein
The common mullein (Verbascum thapsus) is a perennial that originates from Europe, Asia, and Africa. Its appearance changes significantly as the plant matures. Initially, young plants exhibit small, densely packed rosettes of leaves, while mature specimens produce bright yellow flowers on tall stems. This hardy, medicinal plant has gained popularity among nurseries for its potential to alleviate respiratory issues.
However, it’s essential to note that mullein can be quite persistent and spread quickly, more akin to a nuisance weed than an invasive species. Some varieties may be easier to manage than others, but without diligent maintenance, the plant is likely to pop up in unexpected locations around your property.
Purple Loosestrife
Purple loosestrife was first introduced to North America in the 1800s and has since thrived in wetland environments. Characterized by its vibrant fuschia-colored flowers, which grow vertically along the stem, this invasive species is often recommended by nurseries as a visually appealing addition to flower gardens.
However, despite its aesthetic appeal, purple loosestrife poses significant problems due to its rapid spread and voracious appetite for nutrients, which can starve native species of vital sustenance. Furthermore, it has a profound impact on the habitats of many native species, particularly those found in wetland ecosystems. Ultimately, it is recommended to avoid planting this species altogether and instead opt for a more sustainable and environmentally friendly alternative.
Bachelor’s Buttons
The humble cornflower, also known as cerinthe major, is a charming little bloom native to Europe. My own experience with these flowers began when I was warned against planting them by a friend, which piqued my interest and led me to investigate further. From the outside, these tiny invaders are characterized by their vibrant colors – blue, white, purple, or pink hues adorn their delicate stems.
What’s more, they’re easy to grow from wildflower seed packets and even possess an edible quality, making them a popular choice among gardeners. However, it’s essential to note that in certain southern states, the plant’s aggressive nature has led to its prohibition. When considering whether or not to bring these lovely flowers into your garden, weigh the pros and cons carefully, conduct thorough research, and make an informed decision before making a move.
Butterfly bush
While the Butterfly Bush may seem like a lovely addition to your garden, its true nature is less than ideal. Its stunning lilac-like blooms and pleasant aroma are undeniable attractions, but they come at a cost. This shrub can grow up to 16 feet tall, making it a significant presence in your landscape. However, its ease of growth and ability to attract butterflies may not be enough to outweigh the drawbacks.
The seeds of this plant spread quickly, potentially outcompeting native species and altering soil nutrient composition. For those seeking a more balanced choice, there are many other butterfly-friendly perennials and plants that can thrive in your garden without the same level of concerns.
The Bottom Line
Before introducing a new plant into your garden or landscape, it’s crucial to conduct thorough research. A simple online search can reveal valuable information about the plant’s habits and potential impacts. It’s also essential to consider regional factors, as a plant’s invasive status may vary depending on its environment. Remember, knowing is half the battle when it comes to maintaining a healthy and balanced outdoor space.
While not all aggressive plants are inherently invasive, they can still pose challenges in terms of care and maintenance. In these cases, it’s often better to explore alternative options that will provide the desired results without causing unnecessary stress. When seeking advice from gardening professionals, be cautious and don’t hesitate to ask questions. A little skepticism can go a long way in avoiding future headaches.
Have you ever encountered an invasive or aggressive plant in your garden? What was your experience like, and how did you ultimately manage the situation? Were there any particularly problematic plants in your area that caused issues? Share your stories and insights with us by commenting below!
