Ornamental · Amaranthaceae
Globe Amaranth
Gomphrena globosa
Set globe amaranth in full sun and warm, well drained ground, and it dresses the garden in 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 brings a quiet, long-lasting charm to a summer garden with its round, papery flowerheads that echo little clover blooms and hold their color through the season. A tender annual at home in a sunny border or a doorstep pot, it suits the low-fuss, sun-drenched corner of a garden and rewards a busy household that cannot fuss over its plants.
The blooms arrive in pink, purple, white, and red, poised on wiry stems above a trim mound of foliage, an easy match for a gravel path, a cottage bed, or a container by the terrace. Cut and dried, they hold their form and color for a year or more, sliding into everlasting bouquets that carry summer indoors. Out in the garden their color draws butterflies while deer pass them by.
It settles into daily life with almost no demands, thriving in ordinary soil and asking only for the occasional pass to pick off the spent heads. That makes it a natural fit for a first garden or a relaxed weekend plot. Give it a bright, open spot with room for air to move, and the fussier problems keep their distance.
Care
The short version: full sun, average well drained soil, and steady moisture while it is young, then ease off because it takes heat and drought in stride once settled. Feed every couple of weeks through the season and deadhead to keep the flowers coming.
Light
Globe amaranth is at its best in full sun, with at least 6 hours of direct light a day. It manages in part shade, but there it stretches, leans, and flowers far less freely. The brighter the spot, the fuller the harvest of blooms.
Water
Keep the soil evenly moist while the young plants find their feet. Once they have, ease right back, since it takes heat and dry spells well and dislikes sitting wet. Let the top half of the soil dry before the next watering, because sodden ground is what opens the door to disease.
Soil
Average, well drained soil is all this plant asks of a bed. A pH between 6.0 and 7.0 suits it, and it copes with lean ground better than most. What it will not abide is a heavy, waterlogged soil that never quite dries.
Temperature
A lover of warmth, it grows best around 70°F to 75°F (21°C to 24°C). It flourishes through a hot summer but cannot face a frost, so set it outdoors only once the cold has passed for good.
Humidity
Ordinary outdoor air suits it, so there is no figure to worry over. Air movement counts for far more, since still, damp air around a crowded planting is what ushers in mildew and mold.
Feeding
Feed at planting with a water-soluble fertilizer, then keep it up every couple of weeks through the growing season. That light, steady feeding is what sustains the long parade of flowers.
Pruning
Deadhead or gather the spent flowerheads to keep fresh blooms rising all season. Pinching young plants early helps too, drawing out more side branches and a fuller, rounder shape.
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 pass between them and the foliage stays dry.
When to plant
Globe amaranth is a warm season annual that will not stand a frost, so it keeps to the sunny half of the year. Start the seeds indoors in late winter or sow them out once the soil has warmed, and the border fills with flower from early summer 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 of what troubles globe amaranth traces back to damp, crowded plantings or a spot with too little sun. Read the early signs on the leaves and a little more spacing and steadier watering usually set things right. Match what you see below, then act before it spreads through the bed.
Soft gray mold or dark speckling on the foliage
A run of cool, wet weather is what brings on gray mold (Botrytis) and the odd fungal leaf spot. Take off the marked leaves as they appear, and water at the base so the foliage isn't left damp. A more open, generously spaced planting lets air drift through and dry the leaves, keeping the display fresh.
Fix:
- Remove affected plant parts
- Avoid overhead watering and wetting foliage
- Increase spacing and air movement
Only a scattering of seedlings after sowing
Globe amaranth seed is slow to wake and modest in germination, and a chilly seedbed only draws it out further. Soak the seed overnight before sowing and settle it into warm ground held at 70°F to 75°F (21°C to 24°C). Sow a touch more than you need to fill any gaps, and save direct sowing for a border where the soil has properly warmed.
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 pale powdery cast dulling the leaves and stems
That chalky bloom is powdery mildew, a fungus that settles in when a plant has been left dry or has lingered through cool, damp days. Give each plant a little more breathing room, clear out crowded growth, and keep the watering even so the foliage stays dry and the air keeps circulating. Lift away the worst of the coated leaves and discard them to keep the planting looking its best.
Fix:
- Improve air circulation by spacing and thinning
- Water consistently to avoid drought stress
- Remove and discard severely affected foliage
Lanky, leaning stems and a thin show of flowers
Stems that grow lean and floppy with only a few flowers are almost always asking for more sun. Give the plant a brighter spot, or move it, where it catches at least 6 hours of direct light each day. An early pinch of young plants pays off too, coaxing out extra side branches and a fuller sweep of bloom for the border.
Fix:
- Relocate or plant in full sun
- Pinch young plants to encourage branching
Toxicity
For a home that shares its rooms and garden with animals, globe amaranth is reassuringly safe. 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 worst, a pet that eats a lot of any plant may feel briefly unsettled.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
The ASPCA places globe amaranth among the plants that are non-toxic to cats, so it earns a spot in a home that shares its rooms with one. A curious nibble at the papery blooms does no harm, though a large mouthful of any plant can leave a cat drooling briefly or a little queasy.
Dogs None
It sits happily in a dog-friendly household, with no poison in the stems or flowerheads. A dog that overindulges might feel mildly off for a while, and nothing more.
Horses None
Around horses it is non-toxic, so a paddock-side planting or a grazed mouthful raises no concern.
Rabbits Safe
Rabbits can graze the foliage without trouble. There is nothing toxic in it, so the plant stays safe even in a garden they roam.
Livestock Safe
It sits easily near cattle, goats, and sheep, holding nothing toxic to farm animals grazing close by.
Birds Safe
Birds come to no harm around it, and many will visit the dried seed heads, which keeps it safe for garden and pet birds alike.
People Safe
For people it is thoroughly safe, and in some kitchens the dried flowers even steep into a delicate herbal tea. A household with children need not keep it out of reach.
Varieties
Globe amaranth ranges from tall cutting types to tidy dwarfs made for edging, so there is a form for every corner of a scheme. These are the ones you will meet most often.
Strawberry Fields
A taller choice at 18 to 28 inches, it lifts bright red bracts dotted with tiny yellow true flowers to the back of a border.
Las Vegas series
Compact at 16 to 20 inches and offered in pink, purple, and white, it makes an easy palette for a coordinated planting.
Buddy series
A dwarf at just 6 to 8 inches, it slips neatly into edging and small spaces where a taller kind would overwhelm the scheme.
Fireworks
Its shimmering pink bracts finish in yellow tips, and it carries the display longer than most other globe amaranths.
How to propagate
Globe amaranth begins life as seed, and the one thing it asks is a little patience while the slow seed gathers itself.
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
Globe amaranth begins as seed, sown indoors 6 to 8 weeks before your last frost or scattered into warm ground once the cold has lifted. An overnight soak and a warm bed at 70°F to 75°F (21°C to 24°C) coax it into growth within 2 to 3 weeks. Harden the young plants before they meet full sun, and the first flowers arrive to dress the border roughly 12 to 16 weeks after sowing.
Myths
Globe amaranth needs frequent watering to thrive.
Once it has found its footing, this plant carries heat and dry weather with real composure, so a fussy watering routine is beside the point. Keeping to a heavy schedule works against it, since sodden soil and damp leaves are just what invite mildew and rot. Water it well while young, then step back and let the surface dry between drinks.
Globe amaranth is toxic to pets.
The ASPCA lists it as non-toxic to dogs, cats, and horses. A pet that helps itself to a generous portion might feel briefly unsettled, but there is no genuine poison at play here.