Invasive Shade-Tolerant Garden Plants in Maryland

Maryland’s diverse ecosystems, from its forests to shaded suburban landscapes, are at risk from invasive plant species that can outcompete native flora and disrupt local habitats. These invasive plants, often introduced for their ornamental appeal, can spread rapidly in low-light conditions. Understanding these invasive species and selecting native alternatives is essential for preserving Maryland’s natural beauty and biodiversity.

English Ivy (Hedera helix)

List of Invasive Shade-Tolerant Garden Plants in Maryland

1. English Ivy (Hedera helix)

• Description: An evergreen vine with dark green, lobed leaves, often used as ground cover or to climb structures.

• Impact: English Ivy spreads aggressively, smothering native plants and trees, leading to reduced biodiversity and damaging ecosystems.

• Garden Alternative: Virginia Creeper (Parthenocissus quinquefolia) - A native vine that provides similar coverage with vibrant fall color, supporting local wildlife without overwhelming native plants.

2. Japanese Barberry (Berberis thunbergii)

• Description: A small, thorny shrub with bright red berries and small, glossy leaves. Often planted for its ornamental value.

• Impact: Creates dense thickets in shaded areas, crowding out native plants and altering soil chemistry, which can negatively affect surrounding ecosystems.

• Garden Alternative: Red Chokeberry (Aronia arbutifolia) - A native shrub with attractive red berries and brilliant fall foliage, supporting local wildlife and thriving in shaded areas.

3. Garlic Mustard (Alliaria petiolata)

• Description: A biennial herb with heart-shaped leaves and small white flowers, releasing a garlic-like odor when crushed.

• Impact: Garlic Mustard rapidly spreads in shaded woodlands, outcompeting native plants and reducing biodiversity.

• Garden Alternative: Wild Ginger (Asarum canadense) - A native ground cover with heart-shaped leaves that thrives in shaded environments, offering similar coverage without being invasive.

4. Japanese Stiltgrass (Microstegium vimineum)

• Description: An annual grass with thin, pale green leaves that can grow in dense, shaded environments.

• Impact: Japanese Stiltgrass invades forests and shaded areas, outcompeting native ground cover plants and reducing plant diversity.

• Garden Alternative: Eastern Bottlebrush Grass (Elymus hystrix) - A native grass that provides similar coverage in shaded areas while supporting local ecosystems.

5. Lesser Celandine (Ficaria verna)

• Description: A low-growing perennial with shiny, heart-shaped leaves and bright yellow flowers, often found in moist, shaded areas.

• Impact: Forms dense mats that outcompete native spring ephemerals, reducing biodiversity in shaded, moist environments.

• Garden Alternative: Bloodroot (Sanguinaria canadensis) - A native perennial with white flowers that supports early-season pollinators and thrives in similar conditions.

6. Norway Maple (Acer platanoides)

• Description: A large, deciduous tree with broad, dark green leaves, often planted for its dense shade.

• Impact: Produces dense shade that suppresses native undergrowth, leading to reduced biodiversity in forested and shaded areas.

• Garden Alternative: Sugar Maple (Acer saccharum) - A native tree that provides similar shade while supporting a diverse understory of native plants.

7. Periwinkle (Vinca minor)

• Description: A low-growing, evergreen ground cover with glossy leaves and blue or purple flowers. It spreads rapidly and is commonly used in shaded gardens.

• Impact: Periwinkle’s aggressive growth can overshadow and outcompete native ground covers, leading to reduced biodiversity in shaded areas.

• Garden Alternative: Bunchberry (Cornus canadensis) - A native ground cover that offers year-round appeal and supports local wildlife in shaded environments.

8. Chinese Wisteria (Wisteria sinensis)

• Description: A vigorous climbing vine with cascading purple flowers, often planted for its dramatic floral displays.

• Impact: Chinese Wisteria aggressively climbs and smothers native trees and shrubs, causing significant ecological damage in shaded environments.

• Garden Alternative: American Wisteria (Wisteria frutescens) - A native vine with similar purple flowers that supports local wildlife and is less aggressive.

9. Japanese Honeysuckle (Lonicera japonica)

• Description: A fast-growing vine with fragrant white to yellow flowers and dark green leaves. It’s often planted for its attractive blooms.

• Impact: Forms dense mats that smother native plants, reducing biodiversity in shaded and woodland areas.

• Garden Alternative: Trumpet Honeysuckle (Lonicera sempervirens) - A native vine with tubular red flowers that attract hummingbirds and thrive in shaded conditions.

Conclusion

Invasive shade-tolerant plants can have a significant impact on Maryland’s ecosystems by outcompeting native species and altering natural habitats. By choosing native, non-invasive alternatives, gardeners can help maintain ecological balance, support local wildlife, and preserve the natural beauty of Maryland’s landscapes.

For more information and to connect with other gardening enthusiasts, join our Facebook group: Shade Gardening.