Amaranthus, also known as love-lies-bleeding because of its blood-red flowers, can be a temporarily spectacular houseplant. In its natural conditions, it grows to a shrub of up to eight feet tall. When it blooms, it boasts hanging tassels of bright red composed of very small blooms that are striking and look a bit like velvet dreadlocks. These plants are almost never sold as houseplants, but that doesn't mean they can't be grown indoors—their cultural conditions are not demanding, and if you can bring it to flower in the late summer or early autumn, the plant will reward you with showy blooms. You're likely to see them in the outdoor section of the garden center. Amaranthus can also be successfully overwintered, but it's best to start a new crop from seed or cuttings. Fortunately, they produce prolifically from seed and root relatively easily from cuttings. You can tell an older plant by its leaves and stems: both will turn bronze-red with age.
They are not particular about light requirements and can grow in conditions ranging from full sun to light shade. However, they bloom better with more sunlight.
They are also not too picky about water and can survive both low water conditions and periods of heavy watering. As a general practice, it's best to provide them with even moisture and good drainage, though, to prevent root rot.
A rich, peat-based potting soil with excellent drainage is beneficial.
Feed with a weak liquid fertilizer
throughout the growing season. Cut fertilizer back to once a month or so in the winter.
Amaranthus propagates easily from seed, which should be sown into seed-starting soil in early spring. Alternatively, take stem cuttings in the early spring. Rooting hormone will greatly increase your chances of success. Place the young cuttings in a small pot and rest in a warm, bright place until new growth emerges.
Older plants should be repotted every year or two, depending on their overall condition. When repotting, it can also help to trim the plant back and move it up only one plant size. Older plants sometimes need to be staked up to keep the long branches orderly.
The popular species known as love-lies-bleeding is A. caudatus. This plant is well known throughout India and South America, where its leaves, seeds and flowers are used medicinally. This plant belongs to a larger group of plants known as amaranths, all of which feature the tasseled flowers that make it such a lovely plant. Other species in the Amaranthus genus sometimes offered for sale include A. atropurpureus, which has darker red flowers, and A. tricolor, which is more known for its foliage than its relatively small and insignificant flowers.
These are often grown as bedding plants or border plants outside, but indoors they can be used as wonderful hanging plants. They tend to be forgiving plants, but root rot can be deadly, so make sure your pot has adequate drainage. They are also susceptible to a variety of leaf fungal disorders, so be careful not to provide too much humidity or overmist the leaves (although occasional misting might be a good idea if you've in a very arid area). Amaranthus are also susceptible to mealybugs
, and mites. Signs of infestation include tiny webs on plants, clumps of white "powdery" residue, or visible insects on the plant. Treat infestations as soon as possible to prevent them from spreading to the rest of your collection. As always, start with the least toxic treatment option first, only progressing to more serious chemicals if your initial efforts fail.