Globe amaranth (Gomphrena globosa) produces nearly nonstop flowers, making it an all-time favorite for beds, borders, and containers, attracting butterflies and taking the summer heat without missing a beat. Its bright pompoms last a long time in fresh and dried arrangements. Once you plant this versatile annual, you can step back and watch it add continual beauty to your landscape until frost.
You'll have to look closely to see globe amaranth's tiny white or yellow flowers. What stands out are the plant's magenta bracts (modified, colorful leaves that look a little like petals) displayed in cloverlike flowerheads that seem to never quit, even in the hottest weather.
Globe Amaranth Overview
Where to Plant Globe Amaranth
Plant globe amaranth in full sun and well-draining soil in a garden bed or border where you can appreciate this plant's charm. It doesn't like alkaline soil, so amend the garden soil pH if needed. It also grows well in containers. In USDA zones 2-8, globe amaranth is an annual. In zones 9-11, it can be grown as a short-lived perennial.
How and When to Plant Globe Amaranth
Start seeds indoors:
- Start seeds indoors in pots filled with sterile potting mix about six to eight before the last spring frost date.
- Press them into the soil about 1/8 inch and cover them lightly.
- Keep the pots in a warm 70°F-78°F location, and the seeds will germinate in one to two weeks. (They germinate faster if they are soaked overnight in water first.)
- When the seedlings reach 3-5 inches, harden them off and transplant them after the last spring frost, spacing them 12-18 inches apart.
Sow seeds outdoors:
Seed can also be sown outdoors directly in the garden after the last spring frost date for your region. The germination rate is low using this method, so use lots of seeds.
- Prepare a garden bed, adding compost to the garden soil to improve drainage.
- Sow the seeds in the bed and cover them lightly.
- Keep the bed moist until germination; then thin the seedlings to 12-18 inches apart.
Whichever method you choose, you can pinch back young plants to create a bushier habit.
Globe Amaranth Care Tips
Globe amaranth are easy-to-grow annuals. Some plants can grow to 24 inches tall and may need to be staked to keep them from flopping. Cutting flowers may encourage additional blooms.
Light
Globe amaranth grows best in full sun, at least 6 hours a day, but it can tolerate partial shade, though shade reduces the number of blooms and causes the plants to be lanky.
Soil and Water
Globe amaranth needs average, well-drained soil with a decent amount of organic matter. It will grow in sandy or poor soil if it isn't too alkaline. If needed, amend the soil to improve the pH. Once established, globe amaranth tolerates drought but will perform best if given supplemental water throughout the growing season.
Temperature and Humidity
This annual's ability to withstand extremely hot and humid weather makes it invaluable in low-maintenance gardens and mixed containers.
Fertilizer
Globe amaranth doesn't need regular applications of fertilizer. The addition of compost at planting time or a compost mulch for established plants helps build healthy, supportive soil.
Pruning
Other than pinching back the stems to encourage bushiness, globe amaranth doesn't require pruning. Remove any dead or damaged foliage as it occurs. Some gardeners recommend cutting tall varieties back by half early in the growing season. Make the cut just above a leaf set to encourage bushy growth and lessen the need for staking the tallest plants. In Zones 9-11, you can cut the plants back to ground level after they bloom for overwintering.
Potting and Repotting
The shorter varieties of globe amaranth are particularly suited to containers as long as the container offers excellent drainage and is large enough for the plant. Larger varieties require larger pots and pair well with mounding or trailing companion plants. Fill the container with commercial potting soil and position it in full sun. There is no need to repot this annual.
Pests and Problems
Globe amaranth is unaffected by most pests. However, cool and damp weather may cause problems with powdery mildew and fungal leaf spots. Provide good air circulation among plants to prevent these problems by keeping dead foliage and branches cleared away and leaving room between plants when first planting. Globe amaranth is also deer and rabbit-resistant.
How to Propagate Globe Amaranth
The best way to propagate globe amaranth is to harvest the seed from the plants at the end of the blooming season, store them, and then start those seeds indoors six to eight weeks before the last frost of the following spring. To harvest the seed, wait for the flower head to dry thoroughly on the plant and then cut it. Break apart the flower head with your fingers; the seeds are in a fuzzy covering at the base of the bracts. Remove the covering and leave the seeds to dry for another week. Then, store them in an envelope for the next season.
Also, because globe amaranth self-seeds when given the chance, small plants may appear around an existing plant. They can be moved to a new location or given away.
When the parent plant is a cultivar, the harvested seeds and self-seeded plants won't grow into identical plants as the parent.
Innovations
One of the notable discoveries in recent years in the world of globe amaranth is Gomphrena 'Fireworks', which offers a much larger habit, extremely profuse blooming potential, and flatter clustered blossoms. The newer cultivar 'Pink Zazzle' delivers huge blooms on extremely drought-tolerant, free-flowering plants.
Types of Globe Amaranth
'All Around Purple' Globe Amaranth
Gomphrena globosa 'All Around Purple' is a favorite for its rich purple blossoms. It grows to 18 inches tall.
'Bicolor Rose' Globe Amaranth
Gomphrena globosa 'Bicolor Rose' offers dusty-rose flowers that fade to white at the top. It grows 3 feet tall and 18 inches wide.
'Pink Zazzle' Globe Amaranth
Gomphrena globosa 'Pink Zazzle' is a lower-growing variety with fuzzy foliage and jumbo pink blooms that won't quit. It grows to 18 inches tall.
'Fireworks' Globe Amaranth
Gomphrena globosa 'Fireworks' is a wonderful hybrid that can reach up to 4 feet tall and is constantly covered in neon pink blooms all season.
'Lavender Lady' Globe Amaranth
Gomphrena globosa 'Lavender Lady' bears lavender-pink flowers on a 2-foot-tall plant.
'QIS Purple' Globe Amaranth
Gomphrena globosa 'QIS Purple' bears glowing cerise-purple flowers on a 2-foot-tall plant.
'Strawberry Fields' Globe Amaranth
Gomphrena haageana 'Strawberry Fields' offers unusual red flowers. It grows 3 feet tall and 1 foot wide.
Globe Amaranth Companion Plants
Lisianthus
Lisianthus flowers make people ooh and ahh. Some varieties of this annual look like a blue rose. It's such an elegant flower you'd never guess it's native to American prairies. Lisianthus is one of the best cut flowers—it lasts in the vase for two to three weeks but can be challenging to grow. They're extremely tricky to grow from seed, so start with established seedlings. Plant them in rich, well-drained soil in full sun after all danger of frost has passed. Keep them moist, but don't overwater. Tall varieties of lisianthus often need staking to keep their long stems from breaking, but newer dwarf varieties are more carefree. Zones 8-10
Strawflower
Enjoy summer's flowers into fall by growing this brightly colored charmer that dries right on the plant. Use it in dried flower arrangements, wreaths, and homemade potpourri. This easy-to-grow, sun-loving annual is from Australia and is an excellent pick for hot, dry sites. Plant it outdoors after all danger of frost has passed in spring. Zones 8-11
Zinnia
Want fast color for just pennies? Plant zinnias! A packet of seeds will fill an area with gorgeous flowers in an amazing array of shapes and colors—even green—and it will happen in just weeks. There are dwarf types of zinnias, tall types, quill-leaf cactus types, spider types, multicolor, special seed blends for cutting, special blends for attracting butterflies, and more. Zinnias are so highly attractive to butterflies that you can count on having these fluttering guests dining in your garden every afternoon. But to attract the most, plant lots of tall red or hot pink zinnias in a large patch. 'Big Red' is especially nice for this; the flowers are outstanding and excellent for cutting. Zinnias grow quickly from seed sown right in the ground and do best in full sun with dry to well-drained soil. Zones 2-11
Garden Plan for Globe Amaranth
Annual Garden for Full Sun
Planting annuals is about as close to "instant gratification" as you can get in your garden. Follow this annual garden plan for full sun to create a harmonious display of colorful flowers that will bloom throughout the growing season.
Frequently Asked Questions
- How do you overwinter globe amaranth in warm climates?In USDA zones 9-11, gardeners have some luck with growing globe amaranth as a short-lived perennial by cutting it back to the ground for the winter months. In the spring, the plant begins to grow again. In all climates, the plant is a prolific self-seeder, so new plants are likely to appear each spring.
In USDA zones 9-11, gardeners have some luck with growing globe amaranth as a short-lived perennial by cutting it back to the ground for the winter months. In the spring, the plant begins to grow again. In all climates, the plant is a prolific self-seeder, so new plants are likely to appear each spring.
- How long does globe amaranth bloom?Globe amaranth starts blooming in early summer and doesn't stop until frost—no deadheading required. They make excellent dried flowers, too, so if you cut some for drying, the show can keep going after a freeze.
Globe amaranth starts blooming in early summer and doesn't stop until frost—no deadheading required. They make excellent dried flowers, too, so if you cut some for drying, the show can keep going after a freeze.