North America Native Plant

Largeseed Bittercress

Botanical name: Cardamine macrocarpa

USDA symbol: CAMA7

Life cycle: annual

Habit: forb

Native status: Native to the lower 48 states  

Largeseed Bittercress: A Hidden Gem for Texas Native Plant Gardens If you’re looking to add a touch of ephemeral spring beauty to your Texas garden while supporting local biodiversity, largeseed bittercress (Cardamine macrocarpa) might just be the perfect addition. This delicate annual wildflower is one of Texas’s own botanical treasures, ...

Rare plant alert!

Region: Conservation status by state

Status: S3: Status is uncertain but is somewhere between the following rankings: Vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals ⚘

Largeseed Bittercress: A Hidden Gem for Texas Native Plant Gardens

If you’re looking to add a touch of ephemeral spring beauty to your Texas garden while supporting local biodiversity, largeseed bittercress (Cardamine macrocarpa) might just be the perfect addition. This delicate annual wildflower is one of Texas’s own botanical treasures, though you’ve probably never heard of it – and there’s a very good reason for that.

What Makes Largeseed Bittercress Special

Largeseed bittercress is what botanists call a forb – essentially a soft-stemmed herbaceous plant that lacks woody tissue. As an annual, it completes its entire life cycle in just one growing season, making it a fleeting but memorable presence in the spring landscape. True to its name, this member of the mustard family produces relatively large seeds compared to its delicate appearance.

A Texas Native Worth Protecting

This charming wildflower is native to the lower 48 states, but its distribution is quite limited – you’ll only find it growing naturally in Texas. What makes this plant particularly significant is its conservation status: largeseed bittercress is classified as S3 or Vulnerable, meaning it’s at risk due to its restricted range and limited population.

With typically only 21 to 100 known occurrences and an estimated 3,000 to 10,000 individuals in the wild, this is definitely not your everyday garden plant. If you’re considering adding it to your landscape, please ensure you source seeds or plants from reputable native plant suppliers who practice responsible collection methods.

Where and How Largeseed Bittercress Grows

In the wild, you’ll find this adaptable little plant in various moisture conditions. In Texas’s Arid West regions, it’s considered Facultative, meaning it can handle both wet and dry conditions. However, in the Great Plains areas of the state, it leans more toward Facultative Wetland status, preferring consistently moist soils.

The plant thrives in USDA hardiness zones 8-9, which covers most of Texas perfectly. It prefers:

  • Moist to wet, well-draining soils
  • Partial shade to full sun exposure
  • Areas that mimic its natural habitat along stream banks and moist meadows

Garden Design and Landscape Use

Largeseed bittercress works beautifully in several garden settings:

  • Native plant gardens: Perfect for authentic Texas landscapes
  • Wildflower meadows: Adds early spring interest before other plants emerge
  • Naturalized areas: Excellent for low-maintenance, eco-friendly spaces
  • Pollinator gardens: Provides crucial early-season nectar when few other flowers are available

Since it’s an annual that completes its cycle quickly, largeseed bittercress pairs well with perennial natives that will fill in as it fades. Think of it as nature’s opening act – brief but memorable.

Wildlife and Pollinator Benefits

Don’t let its small stature fool you – largeseed bittercress punches above its weight when it comes to supporting local wildlife. Its early spring blooms provide vital nectar for small native bees, beneficial wasps, and other tiny pollinators emerging from winter dormancy. The seeds that give this plant its name also serve as food for small birds and other wildlife.

Growing Tips for Success

Since largeseed bittercress is an annual, your best bet for establishing it is through direct seeding in fall:

  • Timing: Sow seeds in late fall to early winter
  • Soil prep: Ensure good drainage while maintaining consistent moisture
  • Maintenance: Minimal care needed – this plant is adapted to Texas conditions
  • Patience: Allow plants to self-seed for natural populations to develop

Should You Grow Largeseed Bittercress?

If you’re passionate about native Texas plants and want to support conservation efforts, largeseed bittercress is definitely worth considering. Its vulnerable status means every garden population can contribute to the species’ long-term survival. Plus, you’ll be rewarded with delicate white flowers that herald spring’s arrival and support for local pollinators.

Just remember the golden rule: only source this plant from reputable suppliers who collect responsibly. Given its rarity, taking plants from wild populations could harm the very species you’re trying to help.

For gardeners seeking a unique, conservation-worthy native with minimal maintenance requirements and maximum ecological impact, largeseed bittercress offers a perfect opportunity to make a difference – one small but mighty wildflower at a time.

Largeseed Bittercress

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Dilleniidae

Order

Capparales

Family

Brassicaceae Burnett - Mustard family

Genus

Cardamine L. - bittercress

Species

Cardamine macrocarpa Brandegee - largeseed bittercress

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