Common Globe Amaranth
Gomphrena globosa · Globe AmaranthUSDA | Grow Zone
9-11Outdoors all year in zones 9 to 11. Anywhere colder, keep it as a houseplant. Protect it below 32°F.
- Light
- Full sun, 6-8 hours
- Water
- Moderate, top inch dry
- Humidity
- 40-60%
- Temperature
- 70-90°F (21-32°C)
- Difficulty
- Beginner
- Growth
- Moderate
- Mature size
- 12-36 in tall
Gomphrena globosa, commonly known as Globe Amaranth, is a vibrant annual flower native to tropical regions. Its unique globe-shaped blooms add color to gardens and are often used in dried arrangements, making it a favorite among gardeners.
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Ideal temperature
70-90°F is where it grows fastest. Below 32°F cold damage starts.
Spacing and harvest
- Mature size
- 12-36 in tall
- Plant apart
- 12-24 in
- Frost
- Half hardy: light frost only
Everything it needs
9 essentials at a glance
Watering
Gomphrena globosa prefers to be watered moderately.
Allow the top inch of soil to dry out between waterings, typically every 1-2 weeks depending on the season. In hotter months, you may need to water more frequently. Signs of over-watering include yellowing leaves and root rot, while under-watering can cause wilting and crispy leaf edges.
Light
This plant thrives in full sun, requiring at least 6-8 hours of direct sunlight daily.
Ideal placement includes sunny garden beds or containers on patios. It can tolerate some partial shade but will produce fewer flowers in lower light conditions.
Soil
Gomphrena globosa prefers well-draining soil with a pH range of 6.0 to 7.0.
A sandy or loamy potting mix is recommended, often enhanced with perlite or coarse sand to improve drainage. Avoid heavy clay soils to prevent water retention.
Humidity
This plant prefers moderate humidity levels, around 40-60%.
To increase humidity, consider misting the leaves or placing a humidity tray nearby. Signs of low humidity stress include browning leaf tips and wilting.
Temperature
Gomphrena globosa thrives in temperatures between 70-90°F (21-32°C) and is hardy in USDA zones 9-11.
It can tolerate brief periods of heat but may struggle in extreme cold, so protect it from frost during winter months.
Fertilizing
Use a balanced fertilizer with an NPK ratio of 10-10-10, applying every 4-6 weeks during the growing season.
Reduce fertilization in the fall and winter months. Signs of nutrient deficiency include stunted growth and yellowing leaves.
Pruning
Prune Gomphrena globosa in early spring to encourage bushier growth and more blooms.
Use clean, sharp pruning shears to remove any dead or damaged stems. Deadheading spent flowers will promote continuous blooming throughout the season.
Repotting
Repot every 1-2 years or when the plant becomes root-bound.
Choose a pot that is 1-2 inches larger in diameter. Signs it needs repotting include roots growing out of the drainage holes or stunted growth. Carefully remove the plant from its pot, loosen the roots, and place it in fresh potting mix.
Propagation
Propagation can be done through seeds or stem cuttings.
For seeds, sow them indoors 6-8 weeks before the last frost date or directly outdoors after the danger of frost has passed. For stem cuttings, take 4-6 inch cuttings in spring, remove lower leaves, and place them in moist potting mix until roots develop.
When it's unhappy
Yellow leaves
Why it happens
Often caused by over-watering or nutrient deficiency.
How to fix it
Check soil moisture and adjust watering habits. Fertilize with a balanced fertilizer if nutrient deficiency is suspected.
Wilting
Why it happens
Typically due to under-watering or extreme heat.
How to fix it
Increase watering frequency and ensure the plant is not exposed to excessive heat for prolonged periods.
Root rot
Why it happens
Caused by overly wet soil conditions.
How to fix it
Improve drainage by repotting in fresh, well-draining soil and reduce watering frequency.
Browning leaf tips
Why it happens
Often a sign of low humidity or over-fertilization.
How to fix it
Increase humidity levels and reduce fertilizer application.
Pest infestations (aphids, spider mites)
Why it happens
Common pests attracted to stressed plants.
How to fix it
Inspect regularly, and treat infestations with insecticidal soap or neem oil.
Care through the year
Spring
In spring, prune back any dead stems and begin fertilizing every 4-6 weeks. Ensure the plant is getting enough sunlight as it comes out of dormancy.
Summer
During summer, monitor watering closely as the plant may require more frequent irrigation. Deadhead spent flowers to encourage continuous blooming.
Fall
In fall, reduce watering as temperatures cool down. Continue deadheading and prepare the plant for potential frost by bringing container plants indoors.
Winter
In winter, protect the plant from frost if grown outdoors. Reduce watering and avoid fertilizing until spring when growth resumes.
Toxicity & Safety
Gomphrena globosa is non-toxic to pets and children. It is safe to grow around cats and dogs, with no known harmful effects from ingestion.
Good to know
How often should I water my Globe Amaranth?
Water your Globe Amaranth every 1-2 weeks, allowing the top inch of soil to dry out between waterings. Adjust frequency based on the season and temperature.
Why are my Globe Amaranth leaves turning yellow?
Yellow leaves can indicate over-watering or nutrient deficiency. Check the soil moisture and consider fertilizing if the plant appears undernourished.
What type of soil is best for Gomphrena globosa?
Gomphrena globosa prefers well-draining soil with a pH of 6.0 to 7.0. A sandy or loamy mix is ideal, often enhanced with perlite for better drainage.
Can I grow Globe Amaranth in containers?
Yes, Globe Amaranth grows well in containers. Ensure the pot has drainage holes and use a suitable potting mix to promote healthy growth.
What is the best fertilizer for Globe Amaranth?
A balanced fertilizer with an NPK ratio of 10-10-10 is ideal. Apply every 4-6 weeks during the growing season for optimal growth.
How do I propagate Globe Amaranth?
You can propagate Globe Amaranth through seeds or stem cuttings. Sow seeds indoors or directly outdoors after frost, or take cuttings in spring.
What pests should I watch for on Gomphrena globosa?
Watch for aphids and spider mites, which can infest stressed plants. Regular inspections and treatments with insecticidal soap can help manage these pests.
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