- Variety Info
- Sowing Info
- Growing Info
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Variety Info
Family: Asteraceae
Type: Sunflower (Learn more)
Native: North America
Hardiness: Annual
Exposure: Full sun
Bloom Period: Summer to frost
Plant Dimensions: 6'–12' tall
Variety Info: Up to 12"-wide flowers with yellow petals and a brown center. Single type.
Attributes: Attracts Pollinators, Cut Flower, Drought Tolerant, Heat Tolerant, Edible Flower
Sowing Info
When to Sow Outside: RECOMMENDED. 1 to 2 weeks after your average last frost date.
When to Start Inside: 2 to 4 weeks before your average last frost date. Sunflowers are senstive to root disturbance; sow in biodegradable pots that can be planted directly in the ground.
Days to Emerge: 10–15 days
Seed Depth: ¼"–½"
Seed Spacing: A group of 3 seeds every 24"
Thinning: When 3" tall, thin to 1 every 24"
Your hardiness zone is
Growing Info
Harvesting: Seeds are ready to harvest when the back of the head has dried and turned brown, about 4 weeks after the flowers have been pollinated. Petals will have wilted and fallen off, and the seeds will be plump, and colored white with gray/black stripes. Seeds ripen around the outside of the flower first; the ones in the center will ripen last. Average yield is approximately 1 pound per head.
- Juanita L.Verified ReviewerRated 5 out of 5 stars10/29/25Second generation in my high desert garden
I harvested and saved the Mammoth seed heads last summer 2024 and some seeds of course found their way to garden beds. Growing on the edges of beds this spring they were a welcome shade from the hot dry desert climate. 2025 volunteer sunflowers were even bigger, with great seeds harvested.
Which best describes you as a gardener? IntermediateBIBotanical Interests10/31/25Hey Juanita,
Thank you so much for this fantastic 5-star review! "Second generation in my high desert garden" with those volunteer sunflowers that were "even bigger, with great seeds harvested" is exactly what we love to hear about Mammoth Sunflower Seeds - and we absolutely love that your saved seed heads naturally created an even more impressive next generation!
Wow, there's something so satisfying about those self-seeding success stories where nature takes over and rewards you with volunteer plants that actually outperform the original planting! There's nothing quite like discovering that your Mammoth Sunflowers not only thrived in that challenging high desert climate but also provided welcome shade while producing seeds that grew into even more spectacular plants the following year!
It's so wonderful that they found their way to the edges of your beds and became such helpful shade providers during those hot, dry conditions - Mammoth Sunflowers really are such generous plants that keep giving back season after season with their impressive size, practical benefits, and abundant seed production! Your multi-generational growing success and desert climate triumph will be so inspiring for other gardeners who want to discover just how adaptable and self-sustaining Mammoth Sunflower Seeds can be for creating those lasting, productive displays that just keep getting better!
Keep on growing 🌻️
- Mackenzie S.Verified BuyerRated 5 out of 5 stars1/25/255 Stars
Christmas gift for a friend.
He and his girlfriend love it.
- Allen R.Verified BuyerRated 5 out of 5 stars11/23/245 Stars
Amazing seeds throughout the couple years of growing with all kinds of plants from your business. Thank you to all your employees. Gardening keeps me from hurting people.
- Mary O.Verified BuyerRated 5 out of 5 stars11/6/245 Stars
I planted five, and as you can see all five grew. I think they would be taller except I didn’t get them transplanted soon enough, and I also didn’t choose a sunny enough location. I am still thrilled that they all grew and they all have flowers coming! I will be planting them again next year, just in a different location and probably directly in the garden.
- Erle R.Verified BuyerRated 5 out of 5 stars8/3/245 Stars
It was very easy I’m 15 and this is my first gardening season and just put these in the ground and watched them grow. Did plant these in front of my peppers which is my mistake but these are growing very well.