You researched the perfect plants for your garden, relying on easy-to-care-for species and how pretty they look when clustered together. You may have even chosen a few fast-growing varieties to quickly fill in the empty spaces and provide you with a near-instant garden. But what you might not have prepared for is potentially introducing invasive flowers to your beds and borders.
While these plants may look lovely, they pose a real threat to your garden’s health if not regularly pruned. The problem is that many invasive plants are sold in your local home and garden centers as attractive options for planting.
Many of these varieties are common household names and regularly used in landscaping projects.
However, if not tended to accurately and kept under the right amount of control, these plants soon overtake your garden and rob other flowers and shrubs of necessary resources. Luckily, we have gathered the information for you to keep those invasive plants out of your yard for good.
- Tips to Help You Spot Invasive Species
- Fast-Growing Flowers that May Overtake Your Garden
- Garlic Mustard (Alliaria petiolata)
- Privet (Ligustrum): A Popular Hedge Plant that Doesn’t Quit
- Japanese Barberry (Berberis thunbergii)
- Norway Maple (Acer platanoides)
- Kudzu (Pueraria montana): The Most Invasive Plant in U.S.
- Wisteria (Wisteria sinensis)
- English Ivy (Hedera helix): An Ornamental that Smothers All Other Vegetation
- Japanese Honeysuckle (Lonicera japonica)
- Purple Loosestrife (Lythrum salicaria)
- Multiflora Rose (Rosa multiflora): Invasive Flowers with Dense Thickets
- Winter Creeper (Euonymus fortunei)
- Tree-of-Heaven (Ailanthus altissima): A Fast-Growing Plant with No Natural Predators
- Japanese Knotweed (Reynoutria japonica)
- Giant Hogweed (Heracleum mantegazzianum)
Tips to Help You Spot Invasive Species
So what is an invasive plant, and why is it essential to expel it from your yard? There are many reasons why having these plants on your property poses a threat to wildlife habitats.
What makes a plant invasive?
An invasive plant species is considered any non-native plant that is introduced into the ecosystem. Not all non-native plants are invasive, however.
This label only applies to those that pose a potential concern to the safety and healthy growth of the other wildlife surrounding it, including animals and humans.
The biggest issue with invasive plants is that they are difficult to control, whether due to rapid growth or having no natural predators.
Doing this leads to the plant overcrowding other native species, either killing them or diminishing their numbers. In turn, this has a significant impact on the environment, reducing the available food for creatures that thrive on the native species.
Fast-Growing Flowers that May Overtake Your Garden
Sometimes avoiding these plants is impossible, especially if they already exist in your yard or come over from a neighbor’s property. In that case, it’s essential to know how to identify these plants and have a course of action to remove them when required.
Garlic Mustard (Alliaria petiolata)
One of the first types of invasive species many do not realize is a problem is the Garlic Mustard plant. The plant is another non-native species introduced centuries ago when settlers came to the new world and brought the plant for medicinal reasons.
Flowering in March and April, the seeds are what make this plant such a menace. These seeds are as tiny as a grain of sand and just as plentiful, making it easy for them to spread.
The plant itself kills off a type of soil fungi that many plants depend on for moisture and development.
Privet (Ligustrum): A Popular Hedge Plant that Doesn’t Quit
Privet is the type of plant that pops up throughout most gardens. Typically used as hedging, the fast-growing and dense species makes a fantastic privacy border.
However, many consider this plant invasive if not tended to regularly. Part of why Privet poses such a problem is that the plant reproduces asexually.
Even something as small as root fragments left behind in the soil after extraction is enough for the plant to rebuild and grow again. Native to Europe and Great Britain, the plant grows around 2 feet in just one growing season.
Japanese Barberry (Berberis thunbergii)
Another highly invasive species to be on the lookout for is Japanese Barberry. These plants are native to China and Japan and were first introduced during the 1860s.
Originally intended as an ornamental plant, many use it nowadays to create privacy barriers that keep deer out of your gardens. This spiny, deciduous shrub poses a threat to nature purely because it has no real predators to regulate it.
It grows at least 1-2 feet each year, topping out at about 6 feet tall and just as wide. Its most significant threat to the ecosystem is that it takes away space and sunlight from native plants that need it.
Norway Maple (Acer platanoides)
Norway Maple is another example of a plant that seemed like a good idea at the time, before going wrong. These European natives appear in North America as far back as the mid-1700s.
Traditionally used for furniture and even to make violins, they acted as an ornamental shade tree in the United States. The call for these plants increased during the 1930s when many plants were suffering and dying out from Dutch Elm disease.
The fast growth of the Norway Maple, combined with its resistance to diseases, made it an ideal candidate to replace other native plant species. However, these same qualities are what have made it incredibly difficult to control over the years.
Kudzu (Pueraria montana): The Most Invasive Plant in U.S.
The Kudzu vine is another non-native plant that does far more damage than good. The plant came to North America from Japan in the late 1800s as yet another ornamental plant.
In addition to its aesthetic value, the plant acted as foraging food for cattle that needed something more to graze on other than grain. As the roles kudzu used to play began to wane, the vine was left to take over as it saw fit.
The problem is that the plant grows almost a foot per day in ideal conditions and smothers native trees and other plants nearby. It is also said to alter the levels of nitrogen in both the ground and the air, making it dangerous to not only plants but potentially to humans, as well.
Wisteria (Wisteria sinensis)
It’s hard to imagine weddings without the beautiful purple and white flowers of wisteria. These plants are beloved for their charm and elegance, often seen sprawled across fences, trellis, or pergolas for dramatic effect.
However, their longevity and fast growth often lead to complications down the road. Wisteria lives for up to 50 years, in some cases even longer.
Couple this with their ability to grow approximately 10 feet within one growing season, and you have a severe problem. The key is having someone willing to take care of it and prune it regularly, which isn’t always possible for a plant that spans half a century or more.
English Ivy (Hedera helix): An Ornamental that Smothers All Other Vegetation
English Ivy is another European introduction that poses severe problems to other plants’ safety and ecosystems. Today, these ground cover plants appear in beautification programs along roads, as well as a way to control soil erosion with a blanket of vegetation.
They even produce blooms in the form of a delicate white flower with greenish tints. The problem is that ivy continues to grow at a rapid rate, smothering everything in its path, including trees, much like other invasive species such as Japanese stiltgrass.
The vines creep up the sides of trees, reaching up to 90 feet as long as they have something sturdy to cling to. They overtake the canopy and prevent the tree from receiving any kind of sunlight.
Japanese Honeysuckle (Lonicera japonica)
Another non-native species is the Japanese Honeysuckle. This vining plant is a native species of Asia and first appeared in New York in 1806. It produces fragrant white and yellow flowers from April through midsummer, with some staying in bloom through the fall.
Something to consider before adding this plant to your garden is its fast growth rate, which quickly allows it to overtake other plants.
They grow up to three feet each year, topping out at around 30 feet. If you are unable to prune back the plant regularly, it could eventually pose a threat to native plants.
Purple Loosestrife (Lythrum salicaria)
This perennial has been around since the mid-1800s and also does its fair share of damage. The pinkish-purple flowers of loosestrife appear in summer and bloom until late September, making them a desirable addition to many landscapes.
The problem is that the seeds spread so rapidly that it prevents new growth from taking hold. This wildflower poses a massive challenge to agriculture and native wildlife.
Especially in wetlands that depend on a particular type of vegetation for livestock to feed on, this plant threatens the ecosystem and food source. Without native grasses and sedges for the cattle to graze on, the loosestrife severely impacts their ability to find nourishment.
Multiflora Rose (Rosa multiflora): Invasive Flowers with Dense Thickets
One flowering plant did its job a little too well when introduced in the late 1800s. Multiflora Rose was brought over from Japan, Korea, and parts of Eastern China to act as a “living fence” for keeping wildlife both within and outside property borders.
These roses form dense thickets that restrict movement, whether that is any human activity or livestock wandering in search of food. While this seemed like a good idea then, these plants prove more inhibiting that helpful, especially when left unattended.
Also known as the Japanese Rose, this vegetation reaches up to 15 feet and wide, making it difficult to manage once it’s already grown out of control. Not to mention that plant rapidly produces seeds, with many putting out one million a within each year.
Winter Creeper (Euonymus fortunei)
Another new plant brought over to the Americas for decorative purposes, the euonymus frequently appears in landscaping projects.
Winter Creeper is one form to look out for, unlike its relative, the Japanese Euonymus (Euonymus japonicus), which is not an invasive plant. Both are native to Japan, Korea, and China.
Winter Creeper causes problems by reducing the number of nutrients and moisture within the soil, taking a vast majority for themselves, and leaving other plants with nothing. This issue prevents other plants from receiving the necessary resources to grow and reproduce.
Tree-of-Heaven (Ailanthus altissima): A Fast-Growing Plant with No Natural Predators
Known by many names, including Chinese Sumac, the Tree-of-Heaven is this next plant’s most notable moniker. It came to the United States in the 18th century and was developed for commercial use by the 19th century.
The tree grows incredibly fast and has virtually no insect or disease problems. These same resounding qualities are what make the Tree-of-Heaven a potential problem.
Like many on this list, the plant overwhelms native populations within just a few years of growth. Each year the tree grows anywhere from 3-6 feet and quickly overshadows neighboring plant life.
Japanese Knotweed (Reynoutria japonica)
Japanese Knotweed is a perennial that grows in tight, compact shrubs. It reproduces both by seeds and large rhizomes, which are easily identifiable by their deep red color.
When left to grow to their full height, they reach up to ten feet tall. These moderate shrubs multiply, in some cases, as fast as 3-4 inches a day.
Knotweed forms dense thickets that make it difficult for smaller vegetation to receive the necessary sunlight. In turn, this reduces the natural diversity in ecosystems, disrupting the food chain, and so forth.
Giant Hogweed (Heracleum mantegazzianum)
One plant of particular interest to homeowners, both for its invasive characteristics and potentially dangerous tendencies, is Giant Hogweed.
Not only does this plant quickly overtake landscapes, but it also causes harm to humans on contact. Touching this plant results in painful burning of the skin, which may lead to scarring. It is no small plant either.
It quickly reaches its full height of 14 feet, sometimes all in one growing season. It releases tens of thousands of seeds each year, spreading rapidly and is difficult for humans to remove due to its caustic nature.
We hope you enjoyed discovering these non-native plants. The most important thing to know before purchasing these plants, or maintaining existing species in your yard, is to identify potential problems before they get out of hand.
As long as you know how to control the plants, the surrounding wildlife stays safe from harm.
If you found these wildflower tips helpful, please remember to spread the info about these invasive flowers with friends on Facebook and Pinterest.