Russian Mammoth heirloom sunflowers mature a little later in summer but grow to an impressive 3.5m (12′) tall, with heavy heads that can grow to 50cm (20″) in diameter! Plants benefit from staking as the heads get BIG. The seeds are large, tasty and edible; dry roast them in the oven and add optional sea salt. You will know the seeds are mature when chickadees start clinging to the downward pointing faces of the enormous flower heads. This is a fun plant to grow with young people as it becomes truly massive in just a couple of months.

Annual.