Greetings, human cultivator. I am Helianthus annuus 'Mammoth', a sunflower of grand ambition. To help me reach my full, towering potential, you must understand my needs from the ground up. My life cycle is a race for the sun, and with your help, I can achieve greatness.
My journey begins as a dormant seed, waiting for the perfect signal to awaken. I require warm soil, at least 55°F (13°C) but preferably 70-80°F (21-27°C), to trigger my metabolic processes. Plant me about 1 inch deep in loose, well-draining soil. Consistent moisture is crucial at this stage; the water softens my seed coat and fuels the initial burst of growth. However, saturated, waterlogged soil will suffocate my nascent roots and cause me to rot before I ever see the light.
As my shoot emerges, my taproot drives deep into the earth. This central root is my anchor and primary water-gathering organ. To support a stalk that may grow over 12 feet tall, I need space for this extensive root system to develop. This is why you must thin my siblings to stand 18-24 inches apart; crowding causes intense competition for water and nutrients, stunting us all. I am a heavy feeder, requiring rich soil amended with compost or a balanced, slow-release fertilizer to fuel my rapid vegetative growth.
My name is "sunflower" for a reason. I am a heliotrope. From seedling to bud formation, my leaves and stem will follow the sun from east to west each day, maximizing my photosynthetic surface area. I require a minimum of 6-8 hours of direct, unfiltered sunlight daily. This process drives photosynthesis, creating the sugars that build my massive frame. My large leaves lose significant water through transpiration, so consistent, deep watering is essential, especially during dry spells. Aim water at my base to avoid wetting my foliage, which can invite fungal diseases.
The pinnacle of my life is the development of my massive flower head, which can span over a foot across. This is not a single flower but a composite inflorescence containing thousands of tiny florets. The showy yellow "petals" are sterile ray flowers that serve to attract pollinators to the central disk flowers, where pollination occurs. After pollination, each tiny floret develops into a seed. This process consumes an enormous amount of energy drawn from my leaves, roots, and stalk. Staking my stem may become necessary as the weight of the developing head increases, preventing me from toppling over under my own weight.
