(Helianthus annuus) Annual. Monstrously large yellow heads top these archetypal giant sunflowers. Easy and fast-growing, these beauties can reach 12' tall with 10" - 12" flowers!
Produces meaty, delicious seeds that are great for roasting, using as bird seed, or pressing for sunflower oil. Bees will also appreciate this garden addition. Several seeds planted in a row makes a beautiful living fence.
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Plant the seeds 1-2 inches deep and 8-12 inches apart in loose soil and full sun. For the best results, plant sunflower seeds only when the spring is warm and all danger of frost is past, and stagger plantings over several weeks to allow plants to mature at different times to ensure an ongoing supply of ready-to-eat birdseed.
Sunflowers can be planted in all types of soil, and supplemental fertilization is not necessary – in fact, too much fertilization can decrease the seed yield by increasing the height of the stalks and the leaf growth.
Water the seeds daily (twice daily in very hot or dry climates) until the young plants are well established, then water thoroughly every other day.
Weeds should be controlled near sunflowers when the plants are very young, but once sunflowers grow several inches tall they will rapidly become established and weeds are no longer a concern.
When stalks grow taller than three feet, stakes can be used to ensure they do not topple over during high winds, storms or when the seed heads become heavy.
Sunflower seeds will ripen in the fall as the seed heads turn downward and the inner flowers shrivel. Cover the heads with mesh to prevent birds from feasting on them prematurely, or they can be left on the stalks for birds to enjoy directly. To store the seeds, cut the flower heads off each stalk to dry. When the heads are completely dry, the seeds can be rubbed off to be added to feeders, or dry heads can be put in tray or platform feeders without removing the seeds. Store seeds you won’t use right away in a cool, dry place so they will stay fresh and appetizing.