Ornamental · Amaranthaceae
Globe Amaranth
Gomphrena globosa
Give globe amaranth full sun and warm, well drained ground, and it fires off 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 grabs attention with its round, papery flowerheads that mimic little clover blooms and cling to their color for months on end. This tender annual takes off across a huge range of climates, thrives in a sunny bed or a pot, and outlasts most summer flowers when the heat cranks up and the rain stops.
The blooms roll in across pink, purple, white, and red, riding wiry stems above a tidy mound of foliage. Cut and dry them and they lock in their shape and shade for a year or more, which is why they steal the show in everlasting bouquets. Out in the garden they reel in butterflies and send deer packing.
Growing this one is a genuine joy for a beginner. It asks for next to nothing once it settles, powers through poor soil, and keeps pumping out flowers as long as you keep picking the spent heads. Hand it sun and room for air to move, and the worst problems never get a foothold.
Care
The short version: full sun, average well drained soil, and steady moisture while young, then ease off because it storms through heat and drought once established. Feed every couple of weeks through the season and deadhead to keep the flowers coming.
Light
Globe amaranth craves full sun, at least 6 hours of direct light a day. It scrapes by in part shade, but there the plants stretch, flop, and flower far less. Pour on the sun and it rewards you with more blooms to pick.
Water
Keep the soil evenly moist while the young plants dig in and establish. After that, ease right off, because it powers through heat and dry spells and hates wet feet. Let the top half of the soil dry before you water again, since soggy ground throws the door open to disease.
Soil
Average, well drained soil is all it demands. A pH between 6.0 and 7.0 hits the mark, and it shrugs off poor ground better than most. The one thing it flatly refuses is heavy, soggy soil that stays wet.
Temperature
This heat lover hits its stride around 70°F to 75°F (21°C to 24°C). It races through hot summers but caves to frost, so plant it out only once the cold clears off.
Humidity
Ordinary outdoor humidity is plenty, so skip the number chase. Air movement carries far more weight, since still, damp air around crowded plants is what kicks off mildew and mold.
Feeding
Feed at planting with a water-soluble fertilizer, then keep it rolling every couple of weeks through the growing season. That steady, light feeding fuels the long run of flowers.
Pruning
Deadhead or snip off the spent flowerheads to keep fresh blooms firing all season. Pinch young plants back early too, which drives out more side branches and a fuller, bushier plant.
Size & spacing
Plants shoot up to 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 that flat-out refuses frost. Start the seeds indoors in late winter or sow them out once the soil warms, and it flowers from early summer straight through to 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 traces back to damp, crowded conditions or too little sun. Spot the early signs on the leaves and you can usually flip things around with better spacing and steadier watering. Match what you see below, then act before it spreads.
Fuzzy gray mold or dark spots taking hold on the leaves
A cool, wet stretch wakes up gray mold (Botrytis) and a handful of fungal leaf spots. Jump on it early, pluck off the affected parts the moment they show, and switch to watering at the base so the leaves stay dry. Spread the plants out to send air rushing through the foliage, and the trouble loses its grip.
Fix:
- Remove affected plant parts
- Avoid overhead watering and wetting foliage
- Increase spacing and air movement
Barely a seedling to show after sowing
No need to blame yourself, because globe amaranth seed sprouts slowly and germinates low by nature, and cold soil drags it down even more. Soak the seed overnight, keep the soil warm at 70°F to 75°F (21°C to 24°C), and watch the odds swing your way. Scatter a bit extra to plug the gaps, and hold direct sowing until the ground truly warms up.
Fix:
- Soak seed in water overnight before planting
- Maintain 70 to 75°F soil for germination
- Sow extra seed to compensate for low germination
A white powdery dusting creeping over leaves and stems
That coating means powdery mildew has moved in, a fungus that pounces when a plant runs dry or slogs through cool, damp weather. Open the plants up with extra spacing, thin out the crowded growth, and water on a dependable rhythm to keep the leaves dry and the air flowing. Snap off the worst-hit foliage, bin it, and the plant charges right back.
Fix:
- Improve air circulation by spacing and thinning
- Water consistently to avoid drought stress
- Remove and discard severely affected foliage
Lanky, flopping stems and a stingy show of flowers
Thin, floppy plants with barely any bloom are begging for more sun. Shift the plant, or replant it, somewhere it soaks up at least 6 hours of direct light a day, and it firms up fast. Pinch young plants back early to fire off more side branches and a bumper flush of flowers.
Fix:
- Relocate or plant in full sun
- Pinch young plants to encourage branching
Toxicity
Pet owners can breathe easy, because 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
Cats can share the space freely, since the ASPCA lists globe amaranth as non-toxic to cats. A cat that swipes at the papery flowers takes no harm, though a big mouthful of any plant may spark a little drool or a quick stomach upset.
Dogs None
Dogs get the all-clear too, because it is safe for dogs. Let one gnaw a stem or a flowerhead without a second thought, and expect nothing worse than a mild, passing upset if it truly overdoes it.
Horses None
Horses are in the clear as well, with globe amaranth ranking non-toxic to horses and a grazed mouthful posing no real risk.
Rabbits Safe
Rabbits can munch the foliage without worry. Nothing here is toxic, so the plant stays safe if one bounds into the bed.
Livestock Safe
Cattle, goats, and sheep can graze close by with zero concern, since the plant packs nothing toxic for farm animals.
Birds Safe
Birds thrive around it, and plenty flock to the dried seed heads. The plant is safe for backyard and pet birds alike.
People Safe
People are safe with it too, and the dried flowers even steep into a herbal tea in some places, so it counts as safe all the way through. There is no reason to keep children away from it.
Varieties
Globe amaranth shows up in tall cutting types and tidy dwarfs for edging. These are the ones you will run into most often.
Strawberry Fields
A taller standout at 18 to 28 inches, flaunting bright red bracts studded with tiny yellow true flowers.
Las Vegas series
Compact at 16 to 20 inches and bursting out in pink, purple, and white, it packs a whole color mix into one bed.
Buddy series
A dwarf that stops at just 6 to 8 inches, it slots into edging and tight corners where bigger types would muscle in.
Fireworks
Its sparkling pink bracts light up with yellow tips, and it keeps the flowers coming longer than most other globe amaranths.
How to propagate
Globe amaranth grows from seed, and the only hurdle is a bit of patience while the slow seed wakes up.
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
Kick things off from seed and you are halfway to a flower-packed bed. Start it indoors 6 to 8 weeks before your last frost, or sow it right into warm ground once the cold clears out. Soak the seed overnight, keep it toasty at 70°F to 75°F (21°C to 24°C), and it pops up in 2 to 3 weeks. Harden the seedlings off before they hit full sun, and the first flowers burst open about 12 to 16 weeks after sowing.
Myths
Globe amaranth needs frequent watering to thrive.
Once this plant digs in, it powers through heat and dry spells like a champ, so constant watering is wasted effort. Sticking to a heavy schedule backfires, handing mildew and rot the soggy soil and damp leaves they crave. Water it well while young, then back off and let the top of the soil dry between drinks.
Globe amaranth is toxic to pets.
Not so, the ASPCA lists it as non-toxic to dogs, cats, and horses. A pet that gorges on a big helping might get a mild, passing stomach upset, but there is no real poison in play.