North America Native Plant

Southern Amaranth

Botanical name: Amaranthus australis

USDA symbol: AMAU

Life cycle: annual

Habit: subshrub

Native status: Native to the lower 48 states âš˜ Native to Puerto Rico  

Synonyms: Acnida alabamensis Standl. (ACAL3)  âš˜  Acnida australis A. Gray (ACAU4)  âš˜  Acnida cuspidata Bertero ex Spreng. (ACCU3)   

Southern Amaranth: A Native Wetland Wonder for Your Rain Garden If you’re looking to create a thriving wetland garden or restore a soggy corner of your property, meet your new best friend: southern amaranth (Amaranthus australis). This unassuming native annual might not win any beauty contests, but it’s a wetland ...

Southern Amaranth: A Native Wetland Wonder for Your Rain Garden

If you’re looking to create a thriving wetland garden or restore a soggy corner of your property, meet your new best friend: southern amaranth (Amaranthus australis). This unassuming native annual might not win any beauty contests, but it’s a wetland warrior that deserves a spot in every water-loving gardener’s toolkit.

What is Southern Amaranth?

Southern amaranth is a native annual forb that’s perfectly adapted to life in wet places. As an herbaceous plant without woody stems, it completes its entire life cycle in a single growing season. Don’t let its humble appearance fool you – this little plant is a wetland specialist that knows exactly where it belongs.

You might also encounter this plant listed under its former scientific names, including Acnida alabamensis, Acnida australis, or Acnida cuspidata, but Amaranthus australis is the current accepted name.

Where Does Southern Amaranth Call Home?

This native beauty spans across the southeastern United States, naturally occurring in Alabama, Florida, Louisiana, Mississippi, North Carolina, Tennessee, Texas, Virginia, and Puerto Rico. Its range follows the warm, wet coastal and lowland areas where it can access the consistent moisture it craves.

Why Consider Southern Amaranth for Your Garden?

Here’s where southern amaranth really shines – it’s an obligate wetland species, meaning it almost always occurs in wetlands across all regions where it’s found. This makes it an excellent choice for:

  • Rain gardens and bioswales
  • Wetland restoration projects
  • Bog gardens and pond edges
  • Areas with poor drainage or seasonal flooding
  • Native plant gardens focused on ecosystem restoration

While southern amaranth won’t provide the showy blooms of more ornamental plants, its ecological value is substantial. As a native species, it supports local ecosystem health and provides authentic habitat for native wildlife.

Growing Conditions and Care

Southern amaranth is refreshingly straightforward to grow – if you can provide what it needs. This plant thrives in USDA hardiness zones 8-10, matching its natural southeastern range.

Growing Requirements:

  • Moisture: Consistently wet to saturated soils – this plant loves having wet feet!
  • Light: Full sun to partial shade
  • Soil: Tolerates a variety of soil types as long as they stay moist
  • Maintenance: Minimal once established in appropriate conditions

Planting and Establishment

The easiest way to establish southern amaranth is through direct seeding in late spring when soil temperatures warm up. Since it’s an annual, it will complete its life cycle and self-seed for the following year if conditions remain favorable.

Choose a location that stays consistently moist or wet throughout the growing season. This isn’t the plant for well-drained garden beds – save those spots for other natives that prefer drier conditions.

Is Southern Amaranth Right for Your Garden?

Southern amaranth is perfect if you’re working with challenging wet areas that other plants can’t handle. It’s an excellent choice for gardeners interested in native plant restoration, ecological gardening, or managing stormwater naturally.

However, this plant isn’t suitable for traditional ornamental gardens or dry conditions. Its flowers are small and inconspicuous, wind-pollinated rather than attracting showy butterflies or bees. Think of it as a supporting actor rather than the star of your garden show.

The Bottom Line

Southern amaranth might not be the flashiest plant in the native garden world, but it’s a true specialist that excels in its niche. If you have wet, challenging areas where other plants struggle, or you’re passionate about wetland restoration, this humble annual could be exactly what your landscape needs. Sometimes the most valuable plants are the ones that quietly do their job, creating habitat and supporting ecosystems without demanding attention.

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

Atlantic and Gulf Coastal Plain

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Caribbean

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Eastern Mountains and Piedmont

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Great Plains

OBL

Obligate Wetland - Plants with this status almost always occurs in wetlands

Southern Amaranth

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Caryophyllidae

Order

Caryophyllales

Family

Amaranthaceae Martinov - Amaranth family

Genus

Amaranthus L. - pigweed

Species

Amaranthus australis (A. Gray) Sauer - southern amaranth

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