Towering heirloom Mammoth Sunflowers are one of the oldest, most beloved sunflower varieties. Sky-high, 12-foot plants with huge heads are supported by great, sturdy trunks.
Ready to attract pollinators and turn heads in the neighborhood! Roast grey-striped seeds for snacking or feeding wildlife throughout winter.
It is not recommended to start this variety indoors.
Direct sow seeds in average soil in full sun after all danger of frost passes. Sunflowers need a well-drained soil and an open area of the garden. Sow seeds one half inch deep. Space them 18–24 inches apart. Firm soil lightly over seeds, water, and keep evenly moist until germination.
Cut stalks about a foot below the heads when outer seeds are mature (flower heads will become droopy, all of the petals will fall off, and seeds will harden). Hang flower heads upside down in a warm, dry place that is well-ventilated and protected from rodents and insects. Cover sunflower heads with brown paper bags, fine netting, mesh, perforated plastic bags, or cheesecloth. Use a twist tie or rubber band to secure the bag so the seeds don’t fall out.
When seeds are thoroughly dry (after a few weeks), dislodge them by rubbing two heads together, rubbing the seeds with your hand, or using a stiff brush over a big bucket. Allow seeds to dry overnight on a paper towel, then store in a cool, dry place for up to two years.