Many invasive tree species that thrive in the United States come from other countries, primarily Europe and Asia. Although often beautiful, these plants spread rapidly in non-evolving environments to balance growth. These invasive species are a threat to the United States’ natural ecosystems. Many of these invasive trees have escaped from the gardens and landscapes they originally inhabited and are purchased from local nurseries, wholesalers, etc., to grow in the United States. These plants occupy a large area, affect native flora and fauna, and adversely affect the ecosystem.
According to experts, not all non-native plants are harmful. Still, some imported species act like bullies that replace native plants and damage the diverse ecosystems many organisms depend on. Due to their low predators and little competition for resources, these invasive plants replace native plants and increase their diversity until the landscape can no longer support the long-standing native plant, animal, and insect communities.
The perennial kudzu, commonly cultivated in the southeastern United States, originally came from Asia. Japan introduced the kudzu at the Philadelphia Centennial Expo in 1876 in the United States. Soil conservation services planted one million acres of kudzu in the 1930s and 1940s to reduce soil erosion in deforested areas. It was not perceived as invasive until the 1950s.
Once established, kudzu grows at a rate of up to 1 foot per day and 18 meters per year. The USDA estimates that kudzu can spread up to 150,000 acres a year, while the Forest Department estimates it can extend to about 2,500 acres a year. Anyway, kudzu can cover everything from trees, fences, and other permanent structures to anything that gets in the way. Initially advertised as an ornamental plant, it was later broadcast as a feed plant in the southeastern part.
This vigorous species conquers the southeast territory by choking the plants and adding enormous weight to them by peeling and knocking them down to kill the trees. Its native alternatives are Carolina Jessamine and Virginia Creeper.
English ivy was brought to America by settlers to recreate the charm of their native landscaping. However, ivy quickly became invasive and destructive in any new environment, covering trees (and eventually collapsing) and expelling native species from forests and other open areas. The introduction of ivy dates back to the early 18th century when European settlers imported plants as evergreen ground easy to grow. British ivy planting and sales continue in the United States, despite being one of the most common invading crops in the United States.
It can grow in a wide variety of weather conditions, especially on the east and west coasts. English ivy is an aggressively spreading invasive plant that can slowly kill trees by limiting light. It spreads through vegetative propagation and seeds distributed by birds. Its native alternatives are Creeping Mintha, Allegenice Purge, and Creeping Phlox.
Introduced into the country in the late 19th century as an ornamental plant, Japanese barberry is invasive and an ideal hiding place for deer that transmit Lyme disease. These shrubs can grow in deep shade and are especially harmful to northeastern forest areas. In addition, these plants form dense bushes and replace native plants, and birds quickly spread their seeds. Japanese barberry seeds were replaced by Arnold trees from Russia in 1875 as a replacement for European barberry, which was discontinued because it hosted a tribe of black rust, a severe fungus that affects grains. Its local alternative is Shruby St. John’s Wort and Winterberry.
Honeysuckle is often used along highways against erosion. In the United States, these invasive honeysuckles were brought to Long Island, New York, in 1806 for decoration and erosion control. But Japanese honeysuckle does more than reasonable by threatening native plants by capturing all the light, space, and nutrients in that particular area. This plant adapts to various conditions, resulting in increased productivity, especially on the east coast. Honeysuckle is an aggressive plant that chokes, shades, and surrounds other native trees. Birds feed on the fruits of this plant, thereby spreading the honeysuckle seeds.
Botanical researcher John Bartram introduced Norwegian maple from England to the United States in 1756. Its shallow, dense root system competes with lawns and other landscaped plants. These versatile and adaptable trees quickly became popular and were planted as shade trees in urban and rural communities. While some love these adaptable species, it is on the list of invading plants in many states. These replace native trees, dominate both northeastern and northwestern landscapes, and replace native sugar maple and wildflowers.
It is a beautiful but invasive perennial that spreads freely and can damage wetlands and the animals that inhabit them. It was brought to the United States in the early 19th century for ornamental and medicinal purposes. Lythrum salicaria grows invasively in most states and can become the predominant plant species in wetlands. Its native alternatives are Framing Star and New York Verbena.
The wisteria, native to China, is a sight to see, with fragrant purple flowers blooming all over its cover. However, it grows so vigorously that it becomes difficult to manage and is not suitable for growing at home.
The black locust spreads rapidly and is short-lived. Its branches are fragile and strong winds can easily break them. Due to its rapid growth, it is considered invasive and is on the invasive list in many parts.
This woody perennial species is native to Asia and is interrupted by beautiful berries in winter but is considered an invasive species as it hinders the success of native plants.
In recent years, increased travel and international trade have been the primary reason behind many new alien species to the United States. These commonly found plants can be beautiful but invasive. The plants with the highest potential for invasion are productive sowers and active growers who adapt well to various weather conditions. In addition, native species do not evolve with these plants, making it difficult to compete with these invasive species. So it suggested not to buy these invasive trees.