Sunflower, (genus Helianthus), genus of nearly 70 species of herbaceous plants of the aster family (Asteraceae). Sunflowers are native primarily to North and South America, and some species are cultivated as ornamentals for their spectacular size and flower heads and for their edible seeds. The Jerusalem artichoke (Helianthus tuberosus) is cultivated for its edible underground tubers.
The common sunflower (H. annuus) is an annual herb with a rough hairy stem 1–4.5 metres (3–15 feet) high and broad, coarsely toothed, rough leaves 7.5–30 cm (3–12 inches) long arranged in spirals. The attractive heads of flowers are 7.5–15 cm wide in wild specimens and often 30 cm or more in cultivated types. The disk flowers are brown, yellow, or purple, while the petallike ray flowers are yellow. The fruit is a single-seeded achene. Oilseed varieties typically have small black achenes, while those grown for direct seed consumption, known as confection varieties, have larger black-and-white achenes that readily separate from the seed within.
Planting Sunflower Seeds
- Sunflowers should be planted 1 to 1½ inches deep and about 6 inches apart after the soil has thoroughly warmed. If you wish, you can plant multiple seeds and thin them to the strongest contenders when the plants are six inches tall.
- Give plants plenty of room, especially for low-growing varieties that will branch out. Make rows about 30 inches apart. (For very small varieties, plant closer together.)
- A light application of fertilizer mixed in at planting time will encourage strong root growth to protect them from blowing over in the wind.
- Experiment with plantings staggered over 5 to 6 weeks to keep enjoying continuous blooms.
- If you see birds scratching around for the seeds, spread netting over the planted area until seeds germinate. See more ways to keep birds away from your garden.
