Biennial Wormwood: The Uninvited Garden Guest You Should Know About
Ever notice a tall, somewhat scraggly plant popping up in disturbed corners of your yard or along pathways? There’s a good chance you’ve encountered biennial wormwood (Artemisia biennis var. biennis), a non-native forb that’s made itself quite at home across North America. While you probably didn’t invite this plant to your garden party, it’s worth getting acquainted with this widespread visitor.
What Exactly Is Biennial Wormwood?
Biennial wormwood is a non-woody plant that belongs to the large Artemisia family, known for their often aromatic foliage. True to its name, this species typically completes its life cycle over two years – spending its first year establishing roots and foliage, then flowering, setting seed, and dying in its second year. However, it can sometimes behave as an annual under certain conditions.
As a forb, biennial wormwood lacks significant woody tissue and keeps its growing points at or below ground level. This adaptation helps it survive through winter and bounce back when conditions improve.
Where You’ll Find It Growing
Originally from Europe and Asia, biennial wormwood has become a naturalized resident across an impressive range of North American territories. You can find it thriving from Alaska down to South Carolina, and from coast to coast, including most Canadian provinces and nearly all U.S. states. It’s particularly fond of disturbed soils, roadsides, vacant lots, and other areas where the ground has been disrupted.
Should You Plant Biennial Wormwood?
Here’s the straight talk: most gardeners don’t intentionally plant biennial wormwood, and there are good reasons for this. While it’s not classified as invasive or noxious, it offers limited ornamental appeal. The plant produces small, inconspicuous greenish flowers that won’t wow anyone, and its overall appearance is more roadside weed than garden stunner.
If you’re looking for plants in your landscape, you’ll likely find much better options among native species that provide similar benefits with greater ecological value and visual appeal.
Growing Conditions and Characteristics
Biennial wormwood is remarkably adaptable, which explains its widespread distribution. It thrives in:
- Full sun to partial shade conditions
- Poor to average soils
- Disturbed or compacted ground
- USDA hardiness zones 3-9
The plant is quite tolerant of tough growing conditions, making it a survivor in areas where more finicky plants might struggle. However, this same toughness means it can establish itself where you might not want it.
Managing Biennial Wormwood in Your Landscape
If biennial wormwood has appeared in your garden uninvited, you have several options. Since it’s a biennial, preventing it from flowering and setting seed in its second year will eliminate future generations. Hand-pulling young plants is often effective, especially when the soil is moist.
For a more proactive approach, focus on maintaining healthy, dense plantings of desirable species. Biennial wormwood typically establishes itself in bare or disturbed soil, so keeping these areas well-vegetated with your chosen plants can prevent colonization.
Better Native Alternatives
Instead of biennial wormwood, consider these native alternatives that offer similar adaptability but greater ecological benefits:
- Native asters for fall interest and pollinator support
- Wild bergamot (Monarda fistulosa) for aromatic foliage and beautiful flowers
- Native goldenrods for late-season color and wildlife value
- Regional native grasses for ground stabilization
The Bottom Line
While biennial wormwood won’t harm your garden and isn’t considered a serious invasive threat, it’s more of a hitchhiker than a garden star. Understanding what it is and how it grows can help you make informed decisions about managing it in your landscape. When in doubt, focus your energy on cultivating native plants that will provide greater benefits for both your garden’s aesthetics and local wildlife.
Remember, every garden tells a story – and you get to choose whether biennial wormwood plays a starring role or simply makes a brief cameo appearance in yours.
