By Julie Christensen
Most bedding annuals have a compact, tidy form and are used to fill in the spaces left by shrubs and perennials – the real workhorses of any mixed bed. Not so with amaranthus cruentus, also know as red amaranth. Native to Central and South America, this annual plant wastes no time in making a big statement. It is one of the grain amaranth varieties — grown for its grain as well as its beauty.
Amaranthus cruentus grows 3 to 6 feet tall and wide in just one season. It produces extravagant, feathery plumes in shades of red to purple. It’s equally at home among tropical plants or colder climate perennials. Use it as you would annual grasses – as an accent piece or mixed with other plants.
Planting Red Amaranth
Most people buy nursery transplants and plant them outdoors after the last expected frost, but you can also start this plant from seed. Sow the seeds directly in the ground in mild climates, after temperatures are reliably above 60 degrees Fahrenheit, or start it inside four to six weeks before the last expected frost.
When you’re ready to plant amaranthus cruentus, choose a sunny location for it. This fast-growing plant needs at least six to eight hours of sunlight daily to perform well. Amend poor soils well with compost, manure or peat moss. Amaranthus cruentus needs moderately fertile, but consistently moist soil, and grows best with a soil pH between 6.5 and 7.5. Amend acidic soils with lime, or alkaline soils with sulfur, to adjust the soil pH. In dry conditions, water it two or three times weekly, or as needed to keep the soil moist 1 inch beneath the surface.
Fertilize amaranthus after planting and every six weeks with 2 tablespoons of granular 10-10-10 fertilizer per plant. Spread the fertilizer on the soil 6 inches from the plant and till it in lightly.
Pests and Disease Problems
Amaranthus cruentus is subject to more pest and disease problems than most annual plants. Rust, leaf spot and root rots all can be problems. Aphids are also attracted to this plant. Hot, humid weather tend to exacerbate disease and pest issues.
To minimize problems, plant amaranthus cruentus in well-draining soil. Space it so air circulates freely around the plants. Remove and discard diseased leaves and pick up debris off the ground. Because the plants grow for only one season, it’s rarely necessary to treat them with fungicides, although in some cases, you may have to destroy seriously infected plants.
Aphids cause damage by sucking the sap from the leaves and the stems of the plants, causing them to wilt. You might also notice honeydew, a sticky substance secreted by the aphids on the plants and ground. Aster yellows is a fatal plant disease that is spread by aphids and sometimes affects amaranthus cruentus. Deal with the aphids and you’ll reduce the risk of this disease. To combat aphids, spray the leaves of the plants with a steady stream of water or cover both the tops and bottoms of the leaves with insecticidal oil or soap. These chemicals are safer than most pesticides, but they can burn plants if applied on a hot, sunny day.
Other Uses for Amaranth
Amaranth has been grown for centuries as a grain and vegetable. The seeds can be cooked whole, popped like popcorn, or ground into a type of flour. This highly nutritious grain has a protein content of 12 to 17 percent. Amaranth is also high in lysine, an amino acid usually absent from cereal crops.
The leaves of amaranth are often used as a leafy vegetable. Treat them like spinach. Saute them in olive oil and a bit of bacon or steam them and serve them with butter, salt and pepper. Certain amaranth varieties are grown specifically for their leaves, such as Amaranthus tricolor.
To learn more, visit the following links:
Amaranth from Purdue University
Rethinking a Weed: the Truth about Amaranth from United Nations University
How to Cook Amaranth Grain by Kristen Kons
Amaranth, a superfood for the home garden on Youtube.
Julie Christensen learned about gardening on her grandfather’s farm and mother’s vegetable garden in southern Idaho. Today, she lives and gardens on the high plains of Colorado. When she’s not digging in the dirt, Julie writes about food, education, parenting and gardening.