Also known as Giant Helianthus · Giant Or Tall Sunflower · Indian-Potato
Giant Sunflower (Helianthus giganteus) is a tall, striking perennial with multiple yellow flower heads atop sturdy, hairy stems, native to North America.
At-a-glance light, water, soil, and growing conditions from plant data
Full sun
100% intensity
Needs at least 6-8 hours of direct sunlight daily.
Regularly during growth
75% intensity
Keep soil consistently moist, especially during dry spells.
Well-drained, fertile soil
50% intensity
Warm
75% intensity
Prefers temperatures between 20-30°C.
Moderate feeding
50% intensity
Feed with a balanced fertilizer during the growing season.
Safety information from plant toxicity data
| Attribute | Value |
|---|---|
| Toxic for humans | No 0/5 intensity |
| Toxic for pets | No 0/5 intensity |
Non-toxic
Key traits and growing stats from plant data
Watering, pruning, propagation, and repotting details from plant data
Giant Sunflowers are thirsty plants, especially when establishing and during hot, dry periods. Water deeply and consistently, ensuring the soil remains evenly moist but not waterlogged.
Reduce watering slightly once established, but do not allow the soil to dry out completely.
Pruning is generally minimal for Giant Sunflowers. Remove spent flowers to encourage more blooms and tidy up the plant's appearance. Cut back dead or damaged stems at any time.
Some gardeners may pinch back the main stem when young to encourage bushier growth.
Giant Sunflowers are easily grown from seed. Sow seeds directly outdoors after the last frost, or start them indoors 2-4 weeks prior. Seeds require light to germinate.
Transplant seedlings carefully once they have a few true leaves and are hardened off.
Repotting is not typically necessary for Giant Sunflowers as they are usually grown as annuals directly in the ground. If grown in containers, choose a very large pot to accommodate their extensive root system.
Repot in spring if root-bound, using a well-draining potting mix.
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Monthly activity intensity for bloom and fruit across both hemispheres.
Flowering & fruiting calendar
Flowering & fruiting calendar
Photos of Giant Sunflower (Helianthus giganteus)
Where Giant Sunflower (Helianthus giganteus) is found
Density
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Common names and botanical synonyms
Botanical classification
| Rank | Name |
|---|---|
| Kingdom | Plantae |
| Division | Tracheophyta |
| Class | Magnoliopsida |
| Order | Asterales |
| Family | Asteraceae |
| Genus | Helianthus |
| Species | Helianthus giganteus |
Similar in genus Helianthus
Answers based on plant encyclopedia data
