Height 30 cm to 2 m (some varieties can grow to heights of 6 m or more); spread 15 to 45 cm.
Huge flower heads sport bright-yellow petals around a centre of black seeds.
Helianthus annuus (sunflower):
Helianthus annuus giganteus (giant sunflower):
Seed sunflowers directly into the garden or, to get a jump on the season, set out young plants purchased from a garden centre. If you use young plants, be sure they come in individually celled containers: sunflowers don’t like to have their roots disturbed.
How much: Two to three plants; more for ornamental use.
When: Seed as soon as the soil can be worked. Set out young plants one week after the average date of last frost in your area.
Where: Full sun. Prefers rich, well-drained soil; will grow in any soil. Space tall varieties 60 cm apart; space short varieties 45 to 50 cm apart.
Care and Nurture
Sunflowers are very easy to grow! Rain generally provides all the moisture they require, but if conditions are dry, additional watering will produce larger, lusher plants and bigger flowers. Sunflowers self-sow readily, so don’t be surprised if a few plants keep turning up year after year, either in your own yard or your neighbour's.
The flower buds, ray petals, and dried seeds can be eaten If you’re growing sunflowers for the flower buds, choose a perennial or multi-stemmed annual variety, rather than a single-stem annual variety: they produce lots of flower heads. If you’re growing them for the seeds, choose a single-stem variety and don’t harvest petals from the flower heads.
For best flavour: Pampered sunflowers will produce the best growth.
Leaves: Not harvested.
Flowers: Harvest buds as they appear. Clip buds cleanly from stem. Once the flower opens, use only the petals. Pull individual ray petals from growing flower heads, or cut whole flowers and strip the ray petals. Discard the central disc florets.
Seeds: Cut the mature flower heads of sunflowers when they droop, the back of the head is dry and brown, and the seeds are dark and dry. Brush off any remaining petals with your fingers.
Preserving the Harvest
Use the petals and flower buds fresh—they do not store well. I like to tie the mature sunflower heads to the beams of my garage until I’m ready to use them. It’s cool and dry there, and the heads get lots of air movement, preventing decay.
- Grow small varieties in containers. Ikarus and Soraya look great in large containers; you can also try Pacino, Big Smile, and Teddy Bear (my favourite, since its flowers looks like those in the Van Gogh painting).
- Perennial sunflowers tend to deplete the soil where they grow; they should be replanted in a new site every few years, with plenty of well-rotted manure and compost added to the new spot. I prefer to add lots of well-rotted manure and compost each fall so I don’t have to move my plants. Instead, I divide the plant every 3 or 4 years.
- One year, some people who lived down the road from us planted sunflowers close to their corn. Unfortunately, crows swooped down and devastated both crops. To prevent birds from eating all the seeds before you harvest them, cover the flower heads with brown paper bags as soon as they mature.
- The best fertilizers for sunflowers contain twice as much potassium as nitrogen, e.g., 15-15-30.
- Perennial sunflowers tolerate poor soil but they don’t like to dry out.
- Sunflowers are wonderful in backgrounds, borders, and hedges. They’re also a great choice for children's gardens because the seeds are large enough for little fingers to handles and the plants come up quickly and are easily maintained.
- The name Helianthus is derived from the Greek words helios (sun) and anthos (flower). Sunflowers are heliotropic, meaning that they follow the sun. The flowers and leaves turn to the rising sun in the east and follow it across the sky.
- Tall Mammoth sunflowers have heads with a width of up to 40 cm, containing 2000 seeds.
- Each day, a large sunflower uses 17 times as much water as a person does!
- It is purported that chickens will increase their egg laying if they are fed sunflower seeds.
- Sunflower pith is one of the least dense substances known, and is used in many scientific experiments and laboratories.
- In China, sunflowers have been cultivated and used for making delicate silks and cobise ropes.
- Sunflowers have an incredible ability to absorb water from soil. They have been used in the reclamation of marshland in the Netherlands.
- Dried sunflower stems are very hard and make an excellent fuel. Scatter the ashes as a potash fertilizer.
- Boil sunflower petals to make a yellow dye. Sunflower is a good bee plant as it gives the hives large quantities of wax and nectar.
- Sunflower oil has an incredible variety of uses. The oil cake, when warm pressed, yields a less valuable oil used for soap making, candle making, and the art of wool dressing. This cheaper oil is used as a drying oil for mixing paint and is an excellent lubricant.
- The common sunflower is a native of Mexico and Peru. It was cultivated by American Indians 3000 years ago. In the Aztec culture, sunflowers were symbolic of the sun and Aztec sun priestesses were crowned with sunflowers. They carried them in their hands and wore gold jewelry decorated with sunflower emblems. Sunflowers were introduced into Europe in the 16th century by returning Spanish explorers.