Like most true annuals, globe amaranth is easy to grow and it matures fairly quickly. It is a compact plant with upward growing stems that produce cheerful clover-like bracts in a lovely magenta color over a long bloom period from June to frost. These bracts are attractive to butterflies and other pollinators. Structurally, the showy "flowers" of globe amaranth are actually bracts—specialized leaves surrounding the flower. Inside this structure is the true flower, which is insignificant—a tiny yellow bloom that is barely visible.
Globe amaranth is started from seed in the late winter or early spring and planted outdoors after all danger of frost is past.
|Common Name||Globe amaranth|
|Botanical Name||Gomphrena globosa|
|Plant Type||Annual, herbaceous|
|Mature Size||12-24 in. tall, 6-12-in. wide|
|Soil pH||Acidic, neutral|
|Bloom Time||Summer, fall|
|Flower Color||Pink, yellow, white|
|Hardiness Zones||2-11 (USDA)|
|Native Area||Central America|
Globe Amaranth Care
Globe amaranth is normally planted from inexpensive nursery seedling packs. It is a low-maintenance flower with a preference for well-drained soil and a full sun location. Globe amaranth will bloom freely throughout the season without deadheading, but you will probably want to add some of these long-lasting blooms to your vase, so shear away.
Globe amaranth grows best in full sun to part shade. Too much shade reduces blooming and makes the plants lanky as they reach for sun.
Gomphrena grows well in average garden soil to slightly sandy soil. Plants still bloom in heavy clay, but the height may be somewhat stunted. This plant does not like alkaline soil conditions and does best in a pH between 6.1 and 6.5.
Water these plants regularly. Although they tolerate dry spells, globe amaranth will perform best if kept consistently moist—about 1 inch of water per week from rainfall and/or irrigation.
Temperature and Humidity
Globe amaranth will grow well in virtually any climate, but don't plant them outdoors until soil temperatures have warmed up in the spring.
Types of Globe Amaranth
Although the common globe amaranth is a pleasing magenta color, there are numerous improved cultivars with a variety of heights and hues:
- 'All Around Purple' features compact, 3-foot tall container-ready plants with rich magenta blooms.
- 'Bicolor Rose' sports deep lavender flowers with a white cap.
- 'Lavender Lady' has dusky pink flowers that pair well with white or pastel blooms in the landscape.
- 'QIS Formula Mix' comprises a riot of colors which includes pink, orange, red, purple, and white blooms.
- 'Strawberry Fields' has bright red poms on 3-foot plants.
- 'Fireworks' is the hot pink globe amaranth that is different from the usual tight flower form of the typical Gomphrena, producing blooms with an open form, resembling little firecrackers.
There is no pruning involved but pinch young plants to encourage bushy growth.
Propagating Globe Amaranth
Don’t be surprised if you find that the cut flowers have started to root in the vase when you discard your flower arrangement; that’s how easy these plants are to grow. However, the recommended propagation method is from seed. While you can collect seeds from your plants at the end of the season, the seeds from cultivars do not produce a plant that is true to the parent so you might be better off by purchasing seeds. The plants will also freely self-seed in the garden, though again these volunteers might not look the same, and it will take some time for them to mature in the spring.
How to Grow Globe Amaranth From Seed
To start globe amaranth from seed, start it in pots or cell flats, as direct seeding is not recommended. If you live in a cold climate, it is best to start the seeds indoors 6 to 8 weeks before your last frost date, as globe amaranth easily takes 3 months or more to bloom.
Plant more seeds than you need, as germination rates are low. You may increase your germination success by using an electric heat mat.
- Plant the seeds 1/8 inch deep in pots filled with damp, sterile potting mix.
- Keep the soil evenly moist at a temperature between 70 and 78 degrees. The seeds will germinate in 1 to 2 weeks.
- Harden the seedlings off before transplanting them outdoors.
Potting and Repotting
Globe amaranth works well in container gardens as a tall accent plant. Combine it with a mounding plant such as vinca, and a trailing plant such as petunias for a full, lush look. Plant it in a container with large drainage holes and keep in mind that container plants need more frequent watering than plants in garden soil.
Globe amaranth won't need repotting during its single season.
Globe amaranth is a true annual whose life cycle only spans one growing season in all climate zones. The spent plants are pulled and discarded in the fall.
Common Pests & Plant Diseases
It is virtually pest-free, but powdery mildew can sometimes be a problem on crowded plants. Wet conditions can also lead to gray mold and fungal leaf spots.
How to Get Globe Amaranth to Bloom
If your globe amaranth is not blooming, it is most likely lacking sunlight. It needs full sun to bloom.
Common Problems with Globe Amaranth
This low-maintenance annual does not have any common issues. During a cool, rainy summer, it might get more powdery mildew and other fungal diseases than in warm, dry summers.
Where should I plant globe amaranth?
Can globe amaranth flowers be dried?
Do globe amaranth make good cut flowers?
Globe amaranth flowers are very long-lasting, making them great for fresh flower arrangements.