How to Grow Amaranthus Flowers

How to Grow Amaranthus Flowers

Amaranthus is a beautiful plant that has long cascading flowers that bloom all season long. It’s also tall, which makes it a perfect background plant since it grows to a height of 3 to 5-feet. You also don’t have to worry about Amaranthus wilting in the sun since it’s drought-tolerant and it thrives in hot climates.

If you want to learn more about how to grow Amaranthus flowers in your garden keep reading this Amaranthus growing guide for more information.


Best Amaranthus Varieties

Amaranth Flower Set 4 Varieties
Amaranthus Perfecta Ornamental Plant
Amaranthus Molten Fire



Amaranthus Care

  • Sun: Full Sun

  • Height: 3-5 feet (30-60 inches)

  • Spread: 1.25 feet (14-16 inches)

  • Life Cycle: Annual

  • Water Requirements: Moderate

  • Plant Outdoors: Late April to May

  • Plant Indoors: March




Amaranthus Annual or Perennial

Amaranthus is an annual flower that can be grown in USDA hardiness zones 3 to 11. Since they are an annual plant they will die back after the first frost in late fall or early winter. However, Amaranthus will drop thousands of seeds, so you can expect to see lots of Amaranthus seedlings sprouting in your garden once the soil starts to warm in the spring.



Amaranthus Sun or Shade

Amaranthus needs to be planted in a location that gets full sun throughout the day, and they don’t grow well when they are planted in shade.



Starting Amaranthus Indoors

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You can start Amaranthus seeds in a heated seed-starting tray in mid-march or two weeks before the last frost in your area. It’s also important to use a loose fertile potting soil mix that has good drainage. After planting the seeds keep the soil moist and make sure the tray remains covered until the seeds germinate.

Once the seedlings start to mature you can move them to a warm sunny location, or you can place them under a LED Grow Light (Buy Online) until they have two full sets of leaves.

When the seedlings have two full sets of true leaves you can transplant them into small pots and harden them off slowly before placing them in their final location in your flower garden.



Starting Amaranthus From Seed in a Flower Bed

The best way to grow Amaranthus in a flower bed is to directly sow the seeds onto the surface of the soil in an area that gets full sun after the last frost. Then cover the seeds with a thin layer of soil, and keep them watered until the Amaranthus seeds germinate in 10 to 14 days.



Amaranthus Plant Spacing

Amaranthus plants should be spaced 18-inches apart, but you can sow the seeds closer and thin them out once they sprout to avoid getting an uneven stand of Amaranthus plants due to spotty germination.



Amaranthus Soil Requirements

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Amaranthus can produce beautiful flowers in almost any type of soil, but they prefer loose, rich soil with a neutral 6 to 7 pH. However, in some cases, if the soil is too rich then an Amaranthus plant might produce more vegetative growth instead of flowers.



Amaranthus Water Requirements

Amaranthus can tolerate hot dry conditions and it is somewhat drought-tolerant and they don’t like growing in waterlogged soil.

When growing Amaranthus in containers make sure the pots have adequate drainage to avoid root rot and other fungal diseases.



Amaranthus Temperature Requirements

Amaranthus is a heat-tolerant flower and its growth will really start to take off once the temperature reaches 70° F (21° C), and Amaranthus seeds need to be sown when the soil temperature reaches 70°F to 75°F (21°C to 24°C)



Amaranthus Humidity Requirements

Amaranthus tolerates high humidity conditions, and they aren’t highly susceptible to fungal diseases when grown in high humidity environments.



Amaranthus Fertilizer Requirements

Amaranthus should be fertilized every four to six weeks using 2 tablespoons of 10-10-10 NPK fertilizer for each plant to fuel their rapid growth and development.



How To Grow Amaranthus in Containers

Amaranthus is an easy plant to grow in containers. They need to be grown in a large pot though since they are a relatively tall flower.

Amaranthus needs to be planted in a loose well-draining potting soil mix that still retains a good amount of moisture.

When Amaranthus is grown in containers it should be fertilized every 4 to 6 weeks, or you can plant it in a pre-fertilized potting soil mix.

Amaranthus also responds well to foliar feeding using a dilute liquid fertilizer. Also, if you want to promote flower development it’s important to use a high phosphorus low nitrogen fertilizer.



Amaranthus Pests

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Amaranthus will occasionally get attacked by the Pigweed Weevil. This insect will cause the plants to wither and in some cases, the stems might start to bend and collapse

Insecticides can be used to control Pigweed Weevil populations, but in most cases, the best form of management is to uproot and destroy any infested plants.



Amaranthus Diseases

Amaranthus is susceptible to a number of diseases such as Anthracnose, Damping-off, and Wet Rot. Most of these diseases affect young or damaged plants, and in most cases, Amaranthus is a very hardy plant.