North America Non-native Plant

Brittlestem Hempnettle

Botanical name: Galeopsis tetrahit var. arvensis

USDA symbol: GATEA2

Life cycle: annual

Habit: forb

Native status: Non-native, reproduces and persists in the wild in the lower 48 states  

Brittlestem Hempnettle: An Uninvited Garden Guest You Should Know About If you’ve spotted a rather scrappy-looking plant with small pinkish flowers popping up uninvited in your garden beds, you might be looking at brittlestem hempnettle (Galeopsis tetrahit var. arvensis). This annual forb has a knack for showing up where it ...

Brittlestem Hempnettle: An Uninvited Garden Guest You Should Know About

If you’ve spotted a rather scrappy-looking plant with small pinkish flowers popping up uninvited in your garden beds, you might be looking at brittlestem hempnettle (Galeopsis tetrahit var. arvensis). This annual forb has a knack for showing up where it wasn’t planted, and while it’s not necessarily a garden villain, it’s definitely not winning any beauty contests either.

What Exactly Is Brittlestem Hempnettle?

Brittlestem hempnettle is a non-native annual plant that belongs to the mint family, though don’t expect the pleasant aromatics you’d get from its more famous cousins. This European transplant has made itself at home in parts of North America, establishing populations that persist without any help from gardeners.

As a forb, this plant lacks the woody stems of shrubs and trees, instead producing herbaceous growth that dies back each year. The brittlestem part of its common name gives you a hint about its fragile structure – the stems break easily when handled.

Where You’ll Find This Uninvited Guest

In North America, brittlestem hempnettle has been documented growing in Washington state. It tends to favor disturbed soils and agricultural areas, which explains why it might show up in freshly worked garden beds or along field edges.

Should You Plant Brittlestem Hempnettle?

Here’s the short answer: probably not. While this plant isn’t classified as invasive or particularly harmful, it’s not exactly what most gardeners would call ornamental either. Its small, somewhat drab flowers and weedy appearance don’t offer much in terms of garden appeal.

If you’re looking for annual flowers to add to your garden, you’d be much better served by choosing native alternatives that will provide:

  • Better support for local pollinators and wildlife
  • More attractive flowers and foliage
  • Plants adapted to your local climate conditions
  • Species that won’t potentially spread beyond your intended planting area

Better Native Alternatives

Instead of brittlestem hempnettle, consider these native annual options that will give you much more garden bang for your buck:

  • Native wildflowers suited to your region
  • Indigenous pollinator plants
  • Local species recommended by your native plant society

Managing Brittlestem Hempnettle in Your Garden

If this plant has already made itself at home in your garden, don’t panic. As an annual, it completes its life cycle in one year, so preventing it from setting seed is key to management.

Since the stems are quite brittle (living up to that brittlestem name), hand-pulling is usually effective, especially when the soil is moist. Just be sure to remove plants before they flower and set seed if you want to prevent future generations from establishing.

The Bottom Line

While brittlestem hempnettle isn’t necessarily a garden disaster, it’s not a plant most gardeners would choose intentionally. Its weedy appearance and non-native status make it a poor choice compared to the many beautiful native annual options available. If you encounter it in your garden, treating it as the uninvited guest it is – and showing it the door before it sets seed – is probably your best bet.

Remember, every garden space is an opportunity to support local ecosystems, so why not choose plants that truly belong in your neck of the woods?

Brittlestem Hempnettle

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Lamiales

Family

Lamiaceae Martinov - Mint family

Genus

Galeopsis L. - hempnettle

Species

Galeopsis tetrahit L. - brittlestem hempnettle

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA