Sunflower Seeds - Mammoth Grey-Stripe Helianthus annuus
- Annual; Grows 9-12 feet tall
- Giant flowers can reach 10-13 inches in diameter
- Prefers full sun exposure
Shipping Schedule
Seeds are shipped year-round, while perennials & bulbs are shipped seasonally. Pre-ordered bulbs ship at the proper planting time for your zone. Spring pre-orders are placed any time before March 1. Fall pre-orders are placed any time before September 1. These items will not ship immediately, but will be delivered at the ideal time for planting. Orders containing both seeds and bulbs may be split into multiple shipments. Click here for more shipping information.
Pre-Ordered Spring Bulbs & Perennials | Shipping Begins |
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Zones 9 - 12 | Late February to Early March |
Zone 8 | Early to Mid March |
Zone 7 | Mid to Late March |
Zone 6 | Early April |
Zone 5 | Late April |
Zones 2 - 4 | Late April to Early May |
In-season orders ship immediately at the time of purchase to all zones until inventory is depleted. | |
Saffron Crocus & Bearded Iris | Shipping Begins |
All Zones | Late August |
Pre-Ordered Fall Bulbs | Shipping Begins |
Zones 2 - 4 | Mid September |
Zone 5 | Mid to Late September |
Zone 6 | Late September |
Zone 7 | Late September to Early October |
Zones 8 - 12 | Early to Mid October |
In-season orders ship immediately at the time of purchase to all zones until inventory is depleted. | |
Pre-Ordered Fall Perennials* | Shipping Begins |
All Zones | Mid October |
*Amaryllis Bulbs, Hosta Roots, Lily Bulbs, Papaver Roots, Paperwhite Bulbs, Peony Roots & Siberian Iris Roots |
Product Description
Heirloom Mammoth Grey-Stripe Sunflower Seeds -Helianthus annuus
The most familiar and iconic of all the classic sunflowers, our Mammoth Grey Stripe Sunflower seeds may look like the kind you can eat, but we think you'll find them much more rewarding when planted in a sunny location. These beautiful flowers live up to their name and can grow up to a towering 12 feet high with 10+ inch blooms!!
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Fast Facts
Name: Sunflower Seeds - Mammoth Grey-Stripe Botanical Name: Helianthus annuus Life Cycle: Annual Light Requirement: Full Sun Planting Season: Spring Plant Type: Tall green stalks with large yellow blossoms and dark center. Features: Open Pollinated, Cut Flower Garden, Easy to Grow & Maintain, Edible, Attracts Pollinators, Deer Resistant, Drought Tolerant Color: Yellow Blooms: Summer, Late Summer, Early Fall, Fall Plant Height: Up to 144 inches Plant Spacing: 12-18 inches Planting Depth: 1 inch Sowing Method: Direct Sow Cold Stratification: No Seeds per Packet: 3 g Hardiness Zones: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 Ships: Year Round -
Planting Instructions
When to Plant Sunflowers
It is recommended to sow your sunflower seeds directly into your garden rather than start them in starter pots. Sunflowers send down long taproots that can be stunted in small pots. Once all danger of frost has passed and both daytime and nighttime temperatures reach 55F to 60F you are ready to sow your sunflower seeds.
Where to Plant Sunflowers
Sunflowers grow best in full-sun locations – receiving at least 6 to 8 hours of full sun exposure per day. Though sunflowers are not finicky, they do appreciate loose, well-draining soil. Choose a location that is sheltered from strong winds, perhaps along a fence or near a building. Also consider the height that the particular variety will reach.
How to Plant Sunflowers
Once you have chosen your location, dig down to a depth of 2 inches and turn the soil over to loosen it. Many seeds, like poppies, need sun to germinate. This is not the case with sunflowers and in fact need to be pressed 1 inch deep into the soil. If left on the soil surface, more than likely birds will come and eat them before they ever get anywhere close to germination. Final spacing should be 36” apart for giant sunflowers, 24’ apart for regular-sized and 12” apart for miniature varieties.
Caring for and Harvesting Sunflowers
Sunflowers are usually problem-free. Plant early enough so that autumn frosts do not cut your sunflowers’ life cycle short. Too much rainfall before and after germination can cause the seeds to rot or bring on downy mildew. Be sure to seed after the rainy season to avoid this.
If you would like to harvest the seeds to either replant next year, wait until the end of the bloom cycle. Sunflowers blooms often last 30-45 days. Toward the end of this period, the green back of the flower head will begin to turn yellow and will usually droop at this time. You will also see the seeds swelling on the face of the sunflower. Cover the flowers with paper bags to protect them from birds. Cut off the flower heads and leave inside the brown paper bag. Store this bag in a well-ventilated place like a garage until fully dry. Rub along the seeds with the palm of your hand and the seeds should fall right out into your bag, or work over a cookie sheet. Store seeds in a cool, dry environment until you are ready to reseed next year.
To eat: Soak overnight in water, or salt water. Drain, spread on a shallow baking sheet, and roast for 3 hours at 200F or until crisp.
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Planting Video
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Seed Coverage
Amount Recommended Coverage Packet Up to 80 Sq. Ft Ounce Package Up to 625 Sq. Ft 1/4 Pound Package Up to 2,500 Sq. Ft 1 Pound Sack Up to10,000 Sq. Ft 5 Pound Sack Up to 1.3 Acres
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Product Reviews
Review
Mammoth is right!
Our sunflower was 12 feet tall. It was a huge tree! Beautiful! I’d post a pic if I could!
Review
MAMMOTH GREY STRIPE ARE AWESOME!
I had never planted sunflowers before June 2017. They averaged a foot of growth per WEEK finally reaching a height of 6 feet ABOVE my 6-foot white fence! Strangers stopped by to take photos. The heads measured up to 18 inches across! After losing one stalk on a windy day we tied the rest to our fence with twine. This year I couldn't find Mammoth Grey so tried another kind. It's so slow growing I've decided to order Mammoth Grey and start over, even though it's mid-June. These were beyond my wildest dreams!
Review
Very pleased!
we ordered a one ob package of sunflower seeds for wedding favor packets and were very pleased!!
Review
Mammoth GreyStripe Seeds
I'm very pleased with my recent purchase of Mammoth Greystripe Sunflower Seeds. Customer service was great when I had to make a change on my order and the seeds arrived in a timely manner. The seeds themselves look beautiful and healthy and I'm very excited about getting them in the ground soon.
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Sunflower Seeds - Mammoth Grey-Stripe Helianthus annuus
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