Ornamental · Amaranthaceae
Amaranth
Amaranthus caudatus
Give it full sun and warm soil, and amaranth pays you back with trailing tassels from summer into fall.
Full sun
USDA 2–11
3–5 ft · 0.9–1.5 m
Overview
Amaranth is an old plant with a long reach, grown for grain in the Andes and Mexico for thousands of years and kept today for its dramatic flowers. The ornamental favorite, Love-Lies-Bleeding, hangs heavy ropes of crimson or gold tassels that trail almost to the ground. It is an easy annual that asks for warmth and sun and not much else.
There is more than one amaranth, and they split along clear lines. Some are bred for show, with drooping or upright plumes in deep reds, greens, and golds. Others are grain types, grown for the small edible seeds packed into their flower heads, while their weedy cousins, the pigweeds, share the same genus and a less welcome habit.
In the garden amaranth is hard to fail with. It shrugs off heat, tolerates lean soil, and reseeds itself freely once it settles in. The one thing worth knowing is that the foliage can carry high nitrates, which makes a difference if grazing animals share the property.
Care
The short version: plant amaranth in full sun and well-drained, moist soil, keep it watered while it gets going, go easy on the fertilizer, and stake the tall types once the flower spikes form.
Light
Give amaranth full sun for the best color and the sturdiest plants. It will take some afternoon shade, but a shady spot leaves you with weak, leggy growth and thin flower spikes.
Water
Keep the soil evenly moist while the plants are young and getting established. Once they are settled they handle a dry spell, though steady water always gives you the fullest growth.
Soil
Amaranth wants well-drained, moist soil and isn't fussy beyond that. Sharp drainage matters most, since soggy ground is what invites root rot.
Humidity
Ordinary outdoor humidity suits amaranth fine, so there's no target to hit. Good airflow does more for it, keeping the foliage dry and leaf spot at bay.
Feeding
Amaranth rarely needs feeding and does best in lean ground. Go light on nitrogen in particular, because heavy nitrogen drives soft growth and pushes the foliage to store up nitrates.
Pruning
Little pruning is called for. Deadhead or cut the spikes for fresh or dried arrangements, and stake the tall types once the heavy flower heads form so they don't topple.
Size & spacing
Plants reach 3 to 5 feet (91 to 152 cm) tall and spread 12 to 24 inches (30 to 61 cm) across. Give the taller kinds room to stand and air to move around them.
When to plant
Amaranth is a warm-season annual that will not stand frost. Start seed indoors in early spring or sow it straight in the bed once the cold has passed, and the plants flower from midsummer into fall, about 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
Amaranth stays healthy through most seasons, and the few problems it runs into show up on the leaves, the flower spikes, or the roots. Match what you see below, then act before it spreads.
Wilting plant with dark, soft rot at the base
Soggy soil invites Phytophthora blight and root rot, which turns the roots and lower stems dark and mushy until the plant gives out. There's no saving an infected plant, so pull it and destroy it. Fix the drainage before you replant in that spot.
Fix:
- Remove and destroy affected plants
- Improve soil drainage
Angular dark spots boxed in by the leaf veins
Spots that turn angular and water-soaked, often ringed by a yellow halo, point to bacterial leaf spot. Pick off the marked leaves as they show up. Water at the base rather than over the top, since wet foliage is what lets the bacteria spread.
Fix:
- Remove affected foliage
- Avoid overhead watering to reduce leaf wetness
Sticky leaves and curled, distorted new growth
This is an aphid infestation. Look on the flower spikes and leaf undersides for clusters of small soft-bodied insects and the sticky honeydew they leave behind. Knock them off with a hard jet of water, and reach for insecticidal soap only when the numbers get out of hand.
Fix:
- Spray off with a strong jet of water
- Apply insecticidal soap if populations are heavy
Toxicity
Amaranth is safe to grow around cats and dogs, which the ASPCA lists it as non-toxic for. The real concern is grazing animals: the leaves can store up nitrates and oxalates, and a livestock animal eating a large amount of stressed foliage can be poisoned. Keep cattle, horses, and other grazers off big stands of it.
Toxic to
Horses · Rabbits · Livestock · Birds · People
Safe for
Cats · Dogs
Horses Caution
The ASPCA lists the plant as non-toxic to horses, but horses graze, and foliage loaded with nitrates can still trouble any grazing animal. Keep them off a big stand of it, especially after a drought.
Rabbits Caution
A few leaves are unlikely to hurt a rabbit, but the same nitrates and oxalates that affect grazing stock build up in the foliage. Treat it as an occasional taste, not a staple of the diet.
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 happily eat ripe amaranth seed, but heavy grazing on nitrate-rich foliage is a different matter. Let them peck the seed heads and don't worry about the rest.
People Caution
People grow amaranth for grain and greens, and both are eaten cooked. The catch is nitrates and oxalates in leaves from stressed plants, so cook the greens and skip foliage off drought-hit plants.
Cats None
The ASPCA lists amaranth as non-toxic to cats, so a curious nibble is nothing to worry about.
Dogs None
Dogs are fine around amaranth too. The ASPCA puts it on the non-toxic list, and a chewed leaf won't cause harm.
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 covers everything from ground-sweeping ornamentals to upright grain crops. These are the types you are most likely to meet.
Amaranthus caudatus (Love-Lies-Bleeding)
This is the classic ornamental, hung with long, drooping tassels of red or gold that spill toward the ground.
'Viridis'
A green-flowered version of Love-Lies-Bleeding, grown for its unusual chartreuse tassels.
Amaranthus cruentus
An upright grain and ornamental type that holds its plume-like flower heads erect and yields an edible seed.
Amaranthus hypochondriacus (Prince's Feather)
A tall, erect grain amaranth, and the species the ASPCA lists as non-toxic to cats and dogs.
How to propagate
Amaranth is one of the simplest plants to raise from seed, and it will happily seed itself around the garden once you grow it.
SeedEasy
Sow indoors 6 to 8 weeks before last frost, or direct sow outdoors after last frost. · Flowering begins roughly 3 months after sowing
Amaranth grows easily from seed and self-sows with little help. Start it indoors 6 to 8 weeks before your last frost, or scatter seed straight in the bed once the frost danger has passed. Thin or set out the seedlings after that, and the first tassels open about three months later.
Myths
Amaranth flowers are poisonous to cats and dogs.
The ASPCA puts amaranth on its non-toxic list for cats, dogs, and horses, so the flowers pose no real danger to pets. The documented risk is to grazing livestock, where nitrate and oxalate buildup in the foliage does the harm.
Amaranth is edible, so it must be safe for any animal to graze freely.
Pigweeds in this genus pull nitrates and soluble oxalates into their leaves and rank among the leading causes of nitrate poisoning in cattle. Drought stress and high nitrogen push those levels highest, which is exactly when a grazing animal is most at risk.