A Guide to Identifying Invasive Tree and Shrub Species in Southeast Wisconsin
Invasive tree and shrub species pose a significant threat to the natural ecosystems of Southeast Wisconsin. These non-native plants can outcompete native vegetation, disrupt wildlife habitats, and alter local landscapes. Recognizing these invasive species is crucial for effective management and conservation efforts. In this article, we'll explore some common invasive trees and shrubs found in Southeast Wisconsin and provide tips on how to identify them.
Identifying Characteristics:
Common Buckthorn (Rhamnus cathartica): Common buckthorn is a deciduous shrub or small tree with dark green, glossy leaves and sharp thorns along its branches. Its berries turn black when ripe and are a key identifying feature. Buckthorn often forms dense thickets, crowding out native vegetation.
European Buckthorn (Rhamnus frangula): Similar to common buckthorn, European buckthorn has dark green leaves and black berries. However, it lacks thorns and tends to grow taller, reaching heights of up to 20 feet. Its presence can be observed in woodlands, along roadsides, and in disturbed areas.
Tree-of-Heaven (Ailanthus altissima): Tree-of-heaven is a fast-growing deciduous tree with compound leaves that emit a strong odor when crushed. Its bark resembles the skin of a cantaloupe, and it often forms dense colonies, displacing native vegetation. Look for clusters of winged seeds in late summer or early fall.
Japanese Knotweed (Fallopia japonica): Japanese knotweed is a perennial herbaceous plant with bamboo-like stems and large, heart-shaped leaves. Its aggressive growth habit allows it to spread rapidly along waterways, roadsides, and disturbed areas. In late summer, clusters of small white flowers may be visible.
Multiflora Rose (Rosa multiflora): Multiflora rose is a thorny, perennial shrub with arching stems and compound leaves. It produces clusters of small white flowers in spring, followed by red rose hips in late summer. Multiflora rose forms dense thickets, displacing native vegetation and altering wildlife habitats.
Spotting Invasive Species:
Look for dense thickets or monocultures of non-native plants, which may indicate an invasive species.
Take note of unusual growth patterns or aggressive spreading behavior.
Learn to recognize key identifying features such as leaf shape, bark texture, and flower or fruit characteristics.
Consult local resources, such as invasive species guides or online databases, for assistance with identification.
Report sightings of invasive species to local authorities or conservation organizations to help track their spread and facilitate management efforts.
Identifying invasive tree and shrub species is essential for protecting the natural landscapes of Southeast Wisconsin. By learning to recognize these invasive plants and reporting sightings to appropriate authorities, residents can contribute to conservation efforts and help preserve the region's biodiversity. Through collective action and awareness, we can mitigate the impact of invasive species and safeguard the ecological integrity of our communities for future generations.
