Thunberg’s Lespedeza: A Beautiful But Problematic Garden Choice
If you’ve come across Thunberg’s lespedeza (Lespedeza thunbergii) in your gardening research, you might be drawn to its graceful arching branches and late-season purple flowers. But before you add this perennial shrub to your shopping list, there are some important things you should know about this non-native plant and why it might not be the best choice for your garden.
What is Thunberg’s Lespedeza?
Thunberg’s lespedeza is a low-growing perennial shrub that typically stays under 1.5 feet tall, though it can occasionally reach up to 3 feet at maturity. Originally from eastern Asia, including China, Japan, and Korea, this plant has made itself quite at home in North America – perhaps a little too at home.
Where You’ll Find It Growing
This adaptable plant has spread across a wide swath of North America, currently established in Alabama, Arkansas, Connecticut, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Virginia, Wisconsin, and Ontario, Canada. The plant reproduces spontaneously in the wild without human help and tends to persist once established.
The Invasive Plant Problem
Here’s where things get concerning: Thunberg’s lespedeza is listed as a Watch species in Delaware due to its invasive tendencies. While it may not be officially classified as invasive in every state where it grows, its ability to self-seed and establish in natural areas without human intervention makes it a plant that can potentially disrupt local ecosystems.
We recommend avoiding planting Thunberg’s lespedeza in your garden. Even well-intentioned gardeners can inadvertently contribute to the spread of invasive species when plants escape cultivation through seeds carried by wind, water, or wildlife.
What Makes It Appealing (And Why That’s Part of the Problem)
It’s easy to see why gardeners might be tempted by this plant. Thunberg’s lespedeza offers several attractive features:
- Delicate purple-pink pea-like flowers that bloom in late summer and fall
- Graceful, arching growth habit
- Fine-textured foliage
- Attracts bees and butterflies with late-season nectar
- Thrives in full sun to partial shade
- Drought tolerant once established
- Hardy in USDA zones 4-8
These very qualities that make it attractive in gardens – its hardiness, ability to self-seed, and adaptability – are exactly what make it problematic in natural areas.
Better Native Alternatives
Instead of risking the introduction of another invasive species, consider these native alternatives that can provide similar benefits:
- Wild bergamot (Monarda fistulosa) – Provides late-season blooms and attracts pollinators
- New England aster (Symphyotrichum novae-angliae) – Offers fall color and pollinator benefits
- Native goldenrods (Solidago species) – Excellent late-season nectar sources
- Wild lupine (Lupinus perennis) – Another member of the pea family with similar flowers
If You Already Have It
If Thunberg’s lespedeza is already established in your landscape, consider gradually replacing it with native alternatives. The plant can be cut back in late winter or early spring, but be aware that it may continue to self-seed. Removing it entirely and replanting with native species will provide better long-term benefits for local wildlife and ecosystems.
The Bottom Line
While Thunberg’s lespedeza might seem like an attractive, low-maintenance addition to your garden, its invasive potential makes it a plant we can’t recommend. With so many beautiful native alternatives available, you can create an equally stunning landscape while supporting local ecosystems and wildlife. Remember, every plant choice we make in our gardens is an opportunity to either support or potentially harm the natural world around us – let’s choose wisely!
