Invasive Plants on Bald Head Island

What are invasive plants?
Non-native species are plants living in areas in which they do not naturally exist. Non-native plants become invasive plants when they spread outside their area of origin and aggressively dominate or cause harm in a new area. Invasive species can outcompete and lead to the extinction of native plants. In addition, they can decrease biodiversity and permanently alter habitats that native animals depend on for food and shelter. After invading, these plants can compete aggressively for resources because they can tolerate a wide variety of environmental conditions, such as drought, shade, flooding, or extreme temperatures. Most non-native and invasive plants lack natural pest control in their newly invaded area and may be resistant to native predators.

To quantify the threat level of these invasive species, The North Carolina Native Plant Society, with contribution from representatives of state and regional conservation organizations, has created a comprehensive list of all invasive plant species in North Carolina and their “rank,” ranging from “Watch List” to “Severe Threat.” This list can be accessed here. 

How did they get here?
Many invasive and non-native species are introduced to a new area by humans. This can be deliberate or accidental, but often, not by malicious intent. Most invasive plants are introduced with the intention to stabilize soil erosion, improve wildlife habitat, or beautify yards and homes. For instance, Japanese honeysuckle, known for its beautiful and fragrant flowers, is a fast-growing vine that easily smothers native vegetation. English ivy is another vine valued for its beauty and rapid growth, but can form “ivy deserts” where other plants cannot grow. Originally planted with the intention of erosion control, grasses such as bamboo and bermuda are also invasive plants that grow rapidly and outcompete native plants.

What are common invasive plants on Bald Head Island?
Thorny olive, Elaeagnus pungens, is an invasive plant found consistently throughout Bald Head Island. It’s a fast growing shrub often used in landscaping due to its shiny silver appearance and fragrant flowers. It’s resistant to salt spray, drought, and damage from deer browse, which allows it to thrive on the island. While these may seem like good qualities, thorny olive is listed  as invasive in the BHI plant list, with a note, “Don’t plant me!” The North Carolina Native Plant Society lists thorny olive as Rank 2: Significant Threat. The plant grows aggressively, wrapping around neighboring trees or shrubs like a vine. It outcompetes and suffocates native plants, and quickly spreads into neighboring properties. Once established, the plant is hard to control or remove due to its thick branches and easily dispersed seeds.