Ornamental · Amaranthaceae
Amaranth
Amaranthus caudatus
Offer it plenty of sun and warm soil, and amaranth will thank you with trailing tassels right through summer and fall.
Full sun
USDA 2–11
3–5 ft · 0.9–1.5 m
Overview
Amaranth carries a long history in its roots. People have raised it for grain across the Andes and Mexico for thousands of years, and these days many of us keep it simply for its bold flowers. The garden favorite, Love-Lies-Bleeding, lets down thick ropes of crimson or gold tassels that drift nearly to the ground. As an annual it stays wonderfully easy, asking mostly for warmth and sunshine and very little fuss from you.
Not every amaranth is the same, and the family sorts itself into clear groups. Some are raised purely for looks, sending up trailing or upright plumes in rich reds, greens, and golds. Others are the grain kinds, prized for the tiny edible seeds tucked inside their heads, while the weedy pigweeds belong to the same genus and bring a rougher reputation.
Out in the garden, amaranth is a comforting plant to lean on when you are still finding your feet. It copes with heat, makes do with poor soil, and drops seed to come back on its own once it has settled. The single point worth keeping in mind is that the leaves can hold high nitrates, which matters only if grazing animals share your land.
Care
The short version: set amaranth where it gets full sun in well-drained, moist soil, keep it watered while it finds its feet, ease off on fertilizer, and stake the taller kinds once their flower spikes appear.
Light
Treat amaranth to full sun and you will be rewarded with the richest color and the strongest plants. It will put up with a little afternoon shade, though too much shade leaves you nursing weak, leggy stems and skimpy flower spikes.
Water
While the plants are young and settling in, do your best to keep the soil evenly moist. After they are established they can ride out a dry stretch with no trouble, but a little steady water always rewards you with the fullest, lushest growth.
Soil
Amaranth simply wants well-drained, moist soil and asks for nothing more. Good drainage is the part that really counts, because soggy ground is what opens the door to root rot.
Humidity
Everyday outdoor humidity suits amaranth just fine, so you have no number to chase here. What helps far more is good airflow, which keeps the leaves dry and holds leaf spot at bay.
Feeding
Amaranth seldom needs feeding and is happiest in lean ground, so you can take that chore off your list. Be especially sparing with nitrogen, since a heavy hand encourages soft growth and nudges the leaves to stockpile nitrates.
Pruning
There is hardly any pruning to do here, which is a relief. Deadhead or snip the spikes for fresh or dried arrangements, and give the tall kinds a stake once their heavy heads form so a gust does not topple them.
Size & spacing
Expect plants to climb 3 to 5 feet (91 to 152 cm) tall and to fill out 12 to 24 inches (30 to 61 cm) wide. Leave the taller ones a bit of breathing room so they can stand tall with air moving freely around them.
When to plant
Amaranth loves warmth and will not survive a frost, so there is no rush to push it outside. Sow seed indoors in early spring or drop it straight into the bed once the chill has gone, and you can expect blooms from midsummer into fall, roughly three months after sowing.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 6 to 8 weeks before last frost, or direct sow after last frost
- Plant: After danger of last frost has passed
- Harvest: Blooms summer through fall; flowering begins about 3 months after sowing
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Most of the time amaranth sails through the seasons with very little trouble, and the handful of issues that do crop up tend to settle on the leaves, the flower spikes, or the roots. Find what matches your plant below, then step in early and you will usually catch it in good time.
A drooping plant going dark and soft near the soil
When soil stays waterlogged, Phytophthora blight and root rot can move in and leave the roots and lower stem dark and mushy until the plant folds. Sadly a plant this far gone cannot be brought back, so the kindest move is to lift it out and bin it. Sort out the drainage first, and the next planting in that spot will fare much better.
Fix:
- Remove and destroy affected plants
- Improve soil drainage
Sharp-edged dark marks fenced in by the veins
Marks that look angular and water-soaked, often with a soft yellow ring around them, are the signature of bacterial leaf spot. The simple fix is to pluck off the affected leaves whenever you notice them. Watering low at the soil instead of over the top keeps the leaves dry, and dry leaves give the bacteria far less chance to travel.
Fix:
- Remove affected foliage
- Avoid overhead watering to reduce leaf wetness
Tacky film with new growth that curls and warps
If the new growth puckers and a sticky coating appears, you are almost certainly dealing with aphids, and they are nothing to panic over. Check the leaf undersides and the flower spikes for little clusters of soft insects sitting in their own sticky honeydew. A firm blast from the hose clears most of them, and you only need insecticidal soap if a heavy crowd refuses to leave.
Fix:
- Spray off with a strong jet of water
- Apply insecticidal soap if populations are heavy
Toxicity
There is good news for pet owners: amaranth is safe to grow around cats and dogs, and the ASPCA lists it as non-toxic to them. The care needed is for grazing animals, since the leaves can store up nitrates and oxalates, and a grazing animal that eats a lot of stressed foliage can be poisoned. Keeping cattle, horses, and other grazers away from big stands of it is all it takes.
Toxic to
Horses · Rabbits · Livestock · Birds · People
Safe for
Cats · Dogs
Horses Caution
While the ASPCA calls amaranth non-toxic to horses, grazers eat in volume, and foliage carrying high nitrates can unsettle any animal that browses it. Fence them away from a large patch, above all once a dry spell has set in.
Rabbits Caution
A nibbled leaf or two should not bother a rabbit, but the nitrates and oxalates that trouble grazing stock gather in the leaves all the same. Let it be a rare treat rather than something they tuck into every day.
Livestock Severe
Nitrate poisoning in cattle and other grazing animals: increased salivation, labored breathing, incoordination, weak pulse, muscle tremors, weakness, chocolate-brown blood, and death; signs appear about two to six hours after eating. Soluble oxalates and nephrotoxin can also cause kidney damage.
Birds Caution
Birds love a ripe amaranth seed head, and that part is fine to share. Heavy feeding on the nitrate-rich leaves is the only worry, so let them enjoy the seeds and leave the foliage be.
People Caution
Amaranth is grown for both grain and greens, and folks eat each of them cooked. The thing to watch is the nitrates and oxalates that gather in leaves from stressed plants, so always cook the greens and pass on foliage from drought-hit plants.
Cats None
You can relax with cats around, since the ASPCA marks amaranth non-toxic for them and the odd inquisitive nibble will do no harm.
Dogs None
Dogs are in the clear as well. The ASPCA keeps amaranth on its non-toxic list, so a chewed leaf here and there is nothing to fret about.
Safe to grow around dogs and cats; the main risk is to grazing animals eating large amounts of foliage, especially under drought stress or high soil nitrogen.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Amaranth stretches from sprawling ornamentals all the way to tall grain crops. Here are the kinds you are most likely to come across.
Amaranthus caudatus (Love-Lies-Bleeding)
The much-loved ornamental, draped in long ropes of red or gold tassels that pour down toward the soil.
'Viridis'
A green-blooming take on Love-Lies-Bleeding, kept for the surprise of its soft chartreuse tassels.
Amaranthus cruentus
A standing grain and garden type whose plume-shaped heads point upward and ripen into edible seed.
Amaranthus hypochondriacus (Prince's Feather)
A tall, upstanding grain amaranth, and the very species the ASPCA records as non-toxic to cats and dogs.
How to propagate
Few plants are as kind to a beginner from seed as amaranth, and once you have grown it the plant cheerfully sows itself around the garden for you.
SeedEasy
Sow indoors 6 to 8 weeks before last frost, or direct sow outdoors after last frost. · Flowering begins roughly 3 months after sowing
Raising amaranth from seed is about as forgiving as gardening gets, and it will reseed itself around the bed once it feels at home. You can start it under cover 6 to 8 weeks before your last frost, or simply scatter seed where it is to grow after the frost has cleared. Thin the seedlings or plant them out from there, and you can look forward to the first tassels opening around three months on.
Myths
Amaranth flowers will poison a cat or a dog.
You can set this worry aside, because the ASPCA keeps amaranth on its non-toxic list for cats, dogs, and horses, leaving the flowers no threat to your pets. The harm on record falls on grazing livestock, where nitrates and oxalates that build up in the leaves are what cause trouble.
Because amaranth is edible, any animal can safely graze all it wants.
The pigweeds in this genus draw nitrates and soluble oxalates into their leaves and sit among the top causes of nitrate poisoning in cattle. Those levels climb highest under drought stress and high nitrogen, and that is precisely the moment a grazing animal faces the greatest danger.