Sunflower Seeds - Mammoth Grey Stripe

Growing Mammoth Sunflower Garden Seeds

Mammoth sunflower seeds are recommended solely for outdoor growth because of their enormous 9 - 12' height. Mammoth sunflowers grow so vigorously that there is little reason to start seed indoors. Sow directly after final frost in a sunny spot on the north end of the garden and sheltered from strong winds. Always plant tall varieties of sunflowers on the north end of a garden. Mammoth sunflowers are one of the most resilient and fastest growing flowers in all of North America, and will not take long to shadow an entire garden if not properly planned. Plant 2 - 3 Mammoth sunflower seeds ½" deep and 18" apart in average, rich, loamy, and well-drained soil in full sun. Mammoth sunflowers may need staking if plants are growing isolated and away from the support of a garden. Mammoth sunflowers are one of the most resilient and fastest growing flowers in all of North America. Trim declining foliage as summer progresses. Mammoths are susceptible to rust, leaf fungal spots and powdery mildew. Monitor regularly for caterpillars and beetles that may be feeding on the foliage. Mammoth sunflower seeds mature in 90 - 110 days as 108 - 144" tall bushy uprights with a 36 - 40" spread and huge 12" heads of bright yellow sunburst petals with countless deep yellow-orange seeds.

Helianthus annuus is native to the prairies, plains, and meadows of western North America including temperate regions of Canada and Mexico. Many Native American tribes would traditionally plant sunflowers on the north end of their gardens as the "fourth sister" to their "“three sisters" staple crops of corn, beans, and squash.