This is the giant among sunflowers, with towering stems up to 3.6m (12') tall, as thick as a man's leg.

At the top grows a monumental flower head up to 45cm (18") across, heavy with edible seeds. The seed heads tend to nod forward at maturity, facing down. Be sure to get the seeds planted early so the seed heads can mature before the wet weather arrives in September. It's a good idea to direct sow (as opposed to transplanting) these enormous plants so their root growth is not interrupted. They need a solid anchor in order to keep them standing upright.

Annual

Exposure Full-sun

Timing
Direct sow repeatedly after the last frost date. Starting indoors is possible, but does not gain much time. If sunflowers are allowed to get root-bound, they will lack stability at transplant time, and will require staking. Optimal soil temperature for germination: 21-30°C (70-85°F). Seeds should sprout in 10-14 days.

Starting
Sow seeds 5mm-1cm (¼-½”) deep. Space dwarf varieties 15cm (6″) apart, but give the giants lots of room at 1m (3′) between plants.

Companion Planting
Sunflowers planted near rows of corn are said to increase yields. Sunflowers can be used to draw heavy metals, toxins, and even radiation from soil, but should be burned at the end of the season if grown for this purpose. Plant sunflowers amid squash plantings to improve pollination and overall production.