Ornamental · Amaranthaceae
Amaranth
Amaranthus caudatus
Hand it full sun and warm soil, and you'll be rewarded with trailing tassels right through the warm months.
Full sun
USDA 2–11
3–5 ft · 0.9–1.5 m
Overview
Amaranth's been around a long, long time. Folks across the Andes and Mexico have grown it for grain over thousands of years, and these days it mostly earns its keep for those wild flowers. The big garden favorite, Love-Lies-Bleeding, sends down heavy ropes of crimson or gold tassels that nearly brush the soil. And the best part? It's an easy annual that asks for warmth and sun and not a whole lot else.
Here's the thing: there isn't just one amaranth. They sort into clear groups. Some are bred purely to look good, with trailing or upright plumes in deep reds, greens, and golds. Others are the grain types, grown for the little edible seeds tucked inside their heads, and then there are the weedy pigweeds, cousins in the same genus with a habit nobody asks for.
Out in the garden? It's honestly hard to mess up. Amaranth shrugs off the heat, gets by on poor soil, and reseeds itself once it's happy. The one thing worth keeping in the back of your mind is that the leaves can hold high nitrates, and that matters if there are grazing animals sharing the property.
Care
The short version: pop amaranth somewhere sunny with well-drained, moist soil, give it water as it gets going, lay off the fertilizer, and prop up the tall ones as soon as those flower spikes appear.
Light
Give amaranth full sun and you'll get the best color and the toughest plants. It'll handle a bit of afternoon shade, sure, but park it somewhere too shady and you'll end up with weak, leggy growth and skinny flower spikes.
Water
While the plants are young and settling in, try to keep the soil evenly moist. Once they're established they can handle a dry stretch just fine, though a little steady water always gives you the fullest growth.
Soil
Amaranth just wants well-drained, moist soil, and honestly that's about it. Drainage is the big one, because soggy ground is what opens the door to root rot.
Humidity
Regular outdoor humidity is plenty for amaranth, so there's no number you need to hit. What actually helps more is good airflow, which keeps the leaves dry and holds leaf spot off.
Feeding
Amaranth barely ever needs feeding, and it's happiest in lean ground. Go easy on the nitrogen especially, because too much of it drives soft growth and gets the leaves stockpiling nitrates.
Pruning
There's hardly any pruning to bother with. Deadhead or cut the spikes for fresh or dried arrangements, and stake the tall ones once those heavy heads form, otherwise they'll flop right over.
Size & spacing
Plants get to about 3 to 5 feet (91 to 152 cm) tall and fill out 12 to 24 inches (30 to 61 cm) wide. Give the bigger ones some elbow room so air can move around them.
When to plant
Amaranth's a warm-season annual, and frost is a deal-breaker for it. Get seed going indoors in early spring, or wait and sow straight into the bed once the chill clears off, and the blooms roll in from midsummer into fall, roughly three months past 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
For the most part amaranth cruises through the seasons without much drama, and the handful of issues it does hit usually turn up on the leaves, the flower spikes, or the roots. Find your match below, then jump on it before it spreads.
A wilting plant going dark and mushy down low
When the ground stays soggy, Phytophthora blight and root rot tends to move in, and it leaves the roots and lower stems dark and mushy until the plant just gives out. Here's the hard part: once a plant's infected, there's no bringing it back, so pull it and toss it. Sort out the drainage before you put anything new in that spot, okay?
Fix:
- Remove and destroy affected plants
- Improve soil drainage
Dark angular patches penned in by the veins
Spots that look angular and water-soaked, usually with a yellow ring around the edge? That points to bacterial leaf spot. Just pick off the marked leaves as soon as you notice them. And here's the trick: water down at the base instead of over the top, because soggy leaves are exactly what lets the bacteria spread around.
Fix:
- Remove affected foliage
- Avoid overhead watering to reduce leaf wetness
Sticky leaves and new shoots that twist and curl
Seeing a sticky coating and crinkled new growth? That's aphids at work. Flip over a few leaves and check the flower spikes, and you'll spot little clusters of soft insects sitting in the sticky honeydew they leave behind. A good blast of water knocks most of them loose, and you only need insecticidal soap if the crowd really won't quit.
Fix:
- Spray off with a strong jet of water
- Apply insecticidal soap if populations are heavy
Toxicity
If you've got cats and dogs, you can relax, because the ASPCA lists amaranth as non-toxic to both. The real thing to watch is grazing animals: the leaves can build up nitrates and oxalates, and a livestock animal that eats a big helping of stressed foliage can get poisoned. So keep cattle, horses, and any other grazers away from big stands of it.
Toxic to
Horses · Rabbits · Livestock · Birds · People
Safe for
Cats · Dogs
Horses Caution
The ASPCA says amaranth is non-toxic to horses, but here's the catch: horses graze, and leaves packed with nitrates can bother any animal that eats a lot of them. Keep horses out of a big patch, especially after a dry spell.
Rabbits Caution
A leaf or two probably won't hurt a rabbit, but those same nitrates and oxalates that get grazing animals build up in the foliage all the same. Think occasional snack, not everyday meal.
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 ripe amaranth seed, and that's no problem at all. It's only heavy feeding on the nitrate-rich leaves that's a worry, so let them pick at the seed heads and leave it at that.
People Caution
People raise amaranth for its grain and its greens, and both go in the pot before anyone eats them. What's the catch? Nitrates and oxalates in leaves off stressed plants, so always cook your greens and steer clear of foliage from anything that's been through a drought.
Cats None
Cats are totally fine here. The ASPCA calls amaranth non-toxic to them, so if yours sneaks a nibble, there's nothing to stress about.
Dogs None
Same goes for dogs. It's on the ASPCA's non-toxic list, so a chewed leaf isn't going to cause any trouble.
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 runs the whole range, from ground-trailing ornamentals to tall grain crops. Here are the ones you're most likely to bump into.
Amaranthus caudatus (Love-Lies-Bleeding)
This is the one everybody pictures, with long, dangling tassels of red or gold that flow down toward the ground.
'Viridis'
It's a green-flowered spin on Love-Lies-Bleeding, grown for those unexpected chartreuse tassels.
Amaranthus cruentus
This upright type does double duty as ornamental and grain, holding its plume-like heads up high over edible seed.
Amaranthus hypochondriacus (Prince's Feather)
It's a tall, upright grain amaranth, and it's the species the ASPCA lists as non-toxic to cats and dogs.
How to propagate
Amaranth's about as easy to start from seed as it gets, and once you've grown it, it'll happily seed itself all over the garden.
SeedEasy
Sow indoors 6 to 8 weeks before last frost, or direct sow outdoors after last frost. · Flowering begins roughly 3 months after sowing
Growing amaranth from seed couldn't be much easier, and once it's in the garden it pretty much sows itself. You can get a head start indoors 6 to 8 weeks before your last frost, or just toss seed right where it'll grow once the frost danger's gone. Thin the seedlings or plant them out after that, and you'll see those first tassels about three months down the line.
Myths
Amaranth flowers will poison cats and dogs.
Good news here: the ASPCA files amaranth as non-toxic for cats, dogs, and horses, so those flowers won't put any pet in harm's way. It's grazing livestock that actually faces the danger, since the nitrates and oxalates piling up in the leaves are what cause the trouble.
Amaranth is edible, so surely any animal can graze it all day?
Not quite. The pigweeds in this genus stash nitrates and soluble oxalates in the foliage, and they're a top reason cattle end up with nitrate poisoning. Dry spells and heavy nitrogen push those levels sky-high, and that's precisely the moment a browsing animal is most at risk.