GardenersHQ

How to Grow Amaranthus retroflexus Plants in your Garden

Gardener's HQ Guide to Growing Common Amaranth

Better known as Pigweed, the common Amaranth (Amaranthus Retroflexus) reaches an height of about 3 feet (0.9 m).

Although many people conider it to be a weed, this is perhaps one of the best Amaranths to grow if you wish to harvest the seeds for grain.

The leaves of Amaranthus retroflexus also have culinary use, and are often used as a replacement for spinach plants in Mexico – where it is native to.

Common amaranth
Amaranthus retroflexus photograph by Matt Lavin.

This annual amaranth grows well in USDA zones 3 to 11, and is rated at UK hardiness H4. This makes it hardy down to about -10°C (14°F).

Plants carry either male or female flowers (monoecious), and are wind pollinated.

Blooming occurs from the middle of summer through to early autumn

Once blooming has finished seeds will set and rioen from late summer through to themiddle of autumn.

Gardener's HQ Guide to Growing Common Amaranth

Seeds can be sown in their final location towards the end of spring.

Or start in the greenhouse and transplant out following the last frost of spring

Can be grown in pretty much any soil types and acidities. For best results grow in a rich soil.

Plants prefer a moist soil. Water regularly

Grow in a sunny or light shaded area.

Does not like wind, so grow in a sheltered location.

Do not feed with inorganic fertilizers as these plants have very effective photosynthesis (C4 pathway). This can lead to an abundance of unwanted chemicals being available for the leaves and seed. This can result in the plant becoming toxic.

Amaranthus retroflexus Growing and Care Guide

  • Scientific Name: Amaranthus retroflexus
  • Common Name: Common amaranth, Pigweed, Wild beet, Redroot amaranth.
  • Growing Zone: USA: 3 to 11; H4
  • Life Cycle / Plant Type: Annual.

Plant Details

  • Plant Height (Inches): 12 to 36 (30 to 90 cm).
  • Plant Spread (Inches):
  • Time of Bloom: Late spring to early autumn.
  • Flower Details: Small, natively green. Red, purple, pink, orange flowered cultivars available.
  • Leaf Foliage: Green. Ovate leaves.
  • Fruit: Eddible seed in autumn. Glossy, dark.
  • Growth Form: Clumping

Ideal Growing Conditions

  • Best Light Conditions: Partially shady to full sun
  • Rate of Growth: Just under a cm per week when at its greatest (early summer).
  • Suitable Soil Types: Ordinary soil, not too rich, PH 6 to 7 for best results, but will tolerate quite high alkaline and acid soils.
  • Soil Moisture: Good Drainage, Moist

Caring Conditions

  • Level of Maintenance: low
  • Propagation: Seeds: late spring. Can also be grown from cuttings.
  • Pests:
  • Diseases:

Further Information

  • Can Attract:
  • Tolerant of: Fire
  • Best Garden Use:
  • Family: Amaranthaceae
  • Closely Related Species:
  • Miscellaneous: Attractive to birds. Do not grow in soils that are rich in nitrogens as the plant readily takes up this element; this can lead to toxicity.
  • Genus Detail: Amaranthus
  • Further Reading and References: Here and Here

Amaranthus retroflexus makes a good companion plant for many types of vegetables. Some of the ones recommended by the gardenersHQ website include Eggplants, Tomatoes, Peppers and Maize.


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