North America Non-native Plant

Mexican Brassbuttons

Botanical name: Cotula mexicana

USDA symbol: COME15

Life cycle: annual

Habit: forb

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

Mexican Brassbuttons: A Little-Known Annual Worth Understanding If you’ve stumbled across the name Mexican brassbuttons (Cotula mexicana) in your gardening research, you might be wondering what exactly this plant is and whether it belongs in your garden. This small annual is part of the daisy family, though it’s not as ...

Mexican Brassbuttons: A Little-Known Annual Worth Understanding

If you’ve stumbled across the name Mexican brassbuttons (Cotula mexicana) in your gardening research, you might be wondering what exactly this plant is and whether it belongs in your garden. This small annual is part of the daisy family, though it’s not as well-documented as many of its more popular cousins.

What is Mexican Brassbuttons?

Mexican brassbuttons is a non-native annual forb that has found its way into California’s landscape. As a forb, it’s an herbaceous plant without woody tissue – think of it as a soft-stemmed plant that completes its entire life cycle in one growing season. The name brassbuttons likely refers to the small, button-like flowers characteristic of plants in the Cotula genus.

Where Does It Grow?

Currently, Mexican brassbuttons is found in California, though as a non-native species, it originally hails from Mexico (as the name suggests). This introduced plant has managed to establish itself and reproduce in the wild without human assistance.

Garden Suitability and Growing Conditions

Here’s where things get a bit tricky – there’s limited specific information about Mexican brassbuttons’ horticultural requirements and garden performance. What we do know is that it prefers upland conditions, meaning it’s not fond of consistently wet soils. In California’s arid regions, it’s considered an obligate upland plant, while in the state’s mountainous and coastal areas, it shows more flexibility with moisture levels.

Should You Plant It?

While Mexican brassbuttons isn’t currently listed as invasive or noxious, its status as a non-native plant means you might want to consider native alternatives first. California has an abundance of beautiful native annuals that provide similar garden interest while supporting local ecosystems.

Native Alternatives to Consider

Instead of Mexican brassbuttons, consider these California native options:

  • Desert marigold (Baileya multiradiata) – cheerful yellow blooms
  • California poppies (Eschscholzia californica) – the state flower
  • Tidy tips (Layia platyglossa) – white flowers with yellow tips
  • Baby blue eyes (Nemophila menziesii) – delicate blue flowers

The Bottom Line

Mexican brassbuttons remains something of a mystery in the gardening world, with limited cultivation information available. If you’re set on growing it, treat it like other small annuals – provide well-draining soil and avoid overwatering. However, given California’s incredible diversity of native wildflowers, you might find more satisfaction (and ecological benefit) in choosing a native alternative that’s better documented and easier to grow successfully.

Remember, the best garden plants are often those that naturally belong in your region. They’re typically easier to grow, require fewer resources, and provide the greatest benefit to local wildlife and pollinators.

Wetland Status

The rule of seasoned gardeners and landscapers is to choose the "right plant for the right place" matching plants to their ideal growing conditions, so they'll thrive with less work and fewer inputs. But the simplicity of this catchphrase conceals how tricky plant selection is. While tags list watering requirements, there's more to the story.

Knowing a plant's wetland status can simplify the process by revealing the interaction between plants, water, and soil. Surprisingly, many popular landscape plants are wetland species! And what may be a wetland plant in one area, in another it might thrive in drier conditions. Also, it helps you make smarter gardening choices and grow healthy plants with less care and feeding, saving you time, frustration, and money while producing an attractive garden with greater ecological benefits.

Regions
Status
Moisture Conditions

Arid West

UPL

Obligate Upland - Plants with this status almost never occurs in wetlands

Western Mountains, Valleys, and Coast

FACU

Facultative Upland - Plants with this status usually occurs in non-wetlands but may occur in wetlands

Mexican Brassbuttons

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

Asterales

Family

Asteraceae Bercht. & J. Presl - Aster family

Genus

Cotula L. - waterbuttons

Species

Cotula mexicana (DC.) Cabrera - Mexican brassbuttons

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