Red Hempnettle

Red Hempnettle: An Unassuming European Wildflower in North American Gardens

If you’ve spotted a small, purple-flowered plant with square stems popping up in disturbed areas of your garden, you might be looking at red hempnettle (Galeopsis ladanum). This European native has quietly made itself at home across much of North America, though it’s hardly what you’d call a garden showstopper.

What Is Red Hempnettle?

Red hempnettle is an annual forb belonging to the mint family, which explains those telltale square stems. Despite its common name, it’s not actually related to hemp or stinging nettles – the name comes from its somewhat similar appearance to those plants. This modest wildflower typically grows as a branching herb without any woody growth above ground.

Where You’ll Find It

Originally from Europe and western Asia, red hempnettle has established itself across a surprising number of North American regions. You can find it growing wild in Manitoba, New Brunswick, Quebec, and throughout much of the northeastern and Great Lakes states, including Connecticut, Illinois, Indiana, Maine, Massachusetts, Michigan, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, and Vermont. Interestingly, it also pops up as far west as Wyoming.

Should You Grow Red Hempnettle?

Here’s the thing about red hempnettle – it’s not exactly what most gardeners would call ornamental. While its small purple-pink flowers arranged in whorls around the stem have a certain wild charm, this plant is more likely to volunteer in your garden than be something you’d actively seek out at a nursery.

The Good:

• Attracts small pollinators like bees
• Tolerates poor soils and tough conditions
• Adds texture with its square stems and toothed leaves
• Self-seeds readily if you want more

The Not-So-Good:

• Limited aesthetic appeal compared to cultivated flowers
• Can spread aggressively through self-seeding
• Tends to look weedy rather than intentionally planted

Growing Conditions

If red hempnettle has chosen your garden, you’ll find it’s remarkably adaptable. This tough little annual thrives in:

• Full sun to partial shade
• Poor to average soils
• Disturbed areas and edges
• USDA hardiness zones 3-8 (as an annual)

It’s particularly fond of areas where the soil has been disturbed – think along pathways, garden edges, or anywhere you’ve been digging.

Care and Management

The truth is, red hempnettle doesn’t need much care – in fact, it often thrives on neglect. If you’re happy to have it around, simply let it do its thing. It will self-seed and return each year. If you want to control its spread, deadhead the flowers before they set seed, or pull up plants before they flower.

Native Alternatives to Consider

While red hempnettle isn’t invasive, you might prefer to support native ecosystems with plants that evolved alongside local wildlife. Consider these beautiful native alternatives:

• Wild bergamot (Monarda fistulosa) – another mint family member with showy flowers
• Self-heal (Prunella vulgaris) – a native mint with similar growing habits
• Blue vervain (Verbena hastata) – offers similar texture with purple flower spikes

The Bottom Line

Red hempnettle is one of those plants that’s neither wonderful nor terrible – it’s simply there, doing its modest thing in the background of North American landscapes. If it shows up in your garden, you can appreciate its small contribution to pollinator habitat while knowing it won’t cause major problems. But if you’re planning a garden from scratch, you might find more satisfaction in choosing native plants that offer similar benefits with deeper local ecological connections.