Ornamental · Amaranthaceae
Globe Amaranth
Gomphrena globosa
Give it full sun and warm, well drained ground, and globe amaranth throws papery clover-like flowers from summer until frost.
Full sun
Every 5–10 days
70–75°F · 21–24°C
84–112 days
Overview
Globe amaranth earns its place with round, papery flowerheads that look like tiny clover blooms and hold their color for months. It's a tender annual grown across a wide sweep of climates, happy in a sunny bed or a pot, and it stands up to heat and dry spells better than most summer flowers.
The flowers come in pink, purple, white, and red, sitting on wiry stems above a tidy mound of foliage. Cut and dried, they keep their shape and shade for a year or more, which is why they turn up so often in everlasting bouquets. In the garden they pull in butterflies and shrug off deer.
This is a plant for beginners. It asks for little once it's settled, copes with poor soil, and keeps blooming as long as you keep picking the spent heads. Give it sun and room for air to move, and the worst problems stay away.
Care
The short version: full sun, average well drained soil, and steady moisture while young, then ease off because it handles heat and drought once established. Feed every couple of weeks through the season and deadhead to keep the flowers coming.
Light
Globe amaranth wants full sun, at least 6 hours of direct light a day. It will scrape by in part shade, but the plants stretch, flop, and bloom far less. The more sun it gets, the more flowers you pick.
Water
Keep the soil evenly moist while the plants are young and getting established. After that, ease right off, because it handles heat and dry spells well and resents wet feet. Let the top half of the soil dry out before you water again, since soggy ground invites disease.
Soil
Average, well drained soil is all it asks for. A pH between 6.0 and 7.0 suits it fine, and it tolerates poor ground better than most. What it won't forgive is heavy, soggy soil that stays wet.
Temperature
This is a heat lover that grows best around 70°F to 75°F (21°C to 24°C). It thrives through hot summers but won't take a frost, so plant it out only after the cold has passed.
Humidity
Ordinary outdoor humidity is fine, so there's no number to chase. Air movement matters far more, since still, damp air around crowded plants is what brings on mildew and mold.
Feeding
Feed at planting with a water-soluble fertilizer, then keep it going every couple of weeks through the growing season. Regular light feeding supports the long run of flowers.
Pruning
Deadhead or cut the spent flowerheads to keep new blooms coming all season. Pinch young plants back early too, which pushes out more side branches and a fuller, bushier plant.
Size & spacing
Plants reach 12 to 24 inches (30 to 61 cm) tall with a spread of 6 to 12 inches (15 to 30 cm). Set them about 8 inches apart so air can move between them and the leaves stay dry.
When to plant
Globe amaranth is a warm season annual with no tolerance for frost. Start the seeds indoors in late winter or sow them outside once the soil has warmed, and the plants flower from early summer right up until the first frost.
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; soak seed overnight and keep at 70 to 75°F for germination in 2 to 3 weeks
- Plant: After all danger of frost has passed and soil has warmed, spaced about 8 inches apart
- Harvest: Blooms from early summer through fall until frost
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Most trouble with globe amaranth comes from damp, crowded conditions or too little sun. Catch the early signs on the leaves and you can usually turn things around with better spacing and watering. Match what you see below, then act before it spreads.
Gray fuzzy mold or dark spots on the leaves
Cool, wet weather brings on gray mold (Botrytis) and assorted fungal leaf spots. Pull off the affected parts as you spot them and stop wetting the foliage when you water. Open the planting up with wider spacing so air can move through and dry the leaves.
Fix:
- Remove affected plant parts
- Avoid overhead watering and wetting foliage
- Increase spacing and air movement
Few or no seedlings come up after sowing
Globe amaranth seed is slow and naturally low to germinate, and cold soil makes it worse. Soak the seed overnight before you sow and hold the soil at 70°F to 75°F (21°C to 24°C). Sow a little extra to cover the gaps, and wait for warm ground before direct sowing outside.
Fix:
- Soak seed in water overnight before planting
- Maintain 70 to 75°F soil for germination
- Sow extra seed to compensate for low germination
White powdery film coating the leaves and stems
This is powdery mildew, a fungus that shows up when plants are stressed by drought or sit through cool, damp spells. Space the plants out, thin crowded growth, and water on a steady schedule so the leaves stay dry and the air keeps moving. Strip off any badly coated foliage and bin it.
Fix:
- Improve air circulation by spacing and thinning
- Water consistently to avoid drought stress
- Remove and discard severely affected foliage
Stretched, floppy stems carrying few flowers
Thin, leggy plants with sparse bloom almost always mean too little sun. Move the plant or replant it where it gets at least 6 hours of direct light a day. Pinch young plants back early to push out more side branches and a fuller flush of flowers.
Fix:
- Relocate or plant in full sun
- Pinch young plants to encourage branching
Toxicity
Good news for pet owners: globe amaranth is safe all around. The ASPCA lists it as non-toxic to cats, dogs, and horses, and it poses no real danger to other animals or to people. At most, a pet that eats a lot of any plant might get a brief stomach upset.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
The ASPCA lists globe amaranth as non-toxic to cats. A cat that nibbles the papery flowers won't be harmed, though a big mouthful of any plant can bring on a little drooling or a brief stomach upset.
Dogs None
Safe for dogs. Chewing on the stems or flowerheads carries no poison, and the worst a curious dog might get from gorging on it is some mild, passing stomach upset.
Horses None
Globe amaranth is non-toxic to horses and grazing on it poses no real risk.
Rabbits Safe
Rabbits can browse the foliage without concern. There's no toxin here, so the plant is safe if one wanders into the bed.
Livestock Safe
Cattle, goats, and sheep can graze near it safely, since the plant holds nothing toxic to farm animals.
Birds Safe
Birds are fine around it. Many even pick at the dried seed heads, and the plant is safe for backyard and pet birds alike.
People Safe
Globe amaranth is safe for people, and the dried flowers are even brewed into a herbal tea in some places. There's no need to keep children away from it.
Varieties
Globe amaranth comes in tall cutting types and tidy dwarfs for edging. These are the ones you'll run into most often.
Strawberry Fields
A tall type reaching 18 to 28 inches, carrying bright red bracts studded with tiny yellow true flowers.
Las Vegas series
These compact 16 to 20 inch plants come in pink, purple, and white, an easy way to mix colors in one bed.
Buddy series
A dwarf at just 6 to 8 inches tall, it suits edging and tight spaces where bigger types would crowd out.
Fireworks
Its sparkling pink bracts are tipped with yellow, and it blooms longer than most other globe amaranths.
How to propagate
Globe amaranth is grown from seed, and the only catch is patience while the slow seed gets going.
SeedEasy
Start indoors 6 to 8 weeks before last frost, or direct sow after frost and once soil is warm · Germinates in 2 to 3 weeks; blooms about 12 to 16 weeks after sowing
Grow globe amaranth from seed, started indoors 6 to 8 weeks before your last frost or sown straight into warm ground once the cold has passed. Soak the seed overnight and keep it warm at 70°F to 75°F (21°C to 24°C), and it sprouts in 2 to 3 weeks. Harden the seedlings off before they go into full sun, and the first flowers open roughly 12 to 16 weeks after sowing.
Myths
Globe amaranth needs frequent watering to thrive.
Once it has settled in, this plant shrugs off heat and dry spells with ease. Soaking it on a constant schedule does more harm than good, since soggy soil and damp leaves invite mildew and rot. Water it well while young, then ease off and let the top of the soil dry between drinks.
Globe amaranth is toxic to pets.
The ASPCA lists it as non-toxic to dogs, cats, and horses. A pet that eats a large amount might get a mild, passing stomach upset, but there's no real poison to worry about.