Bright and colourful, tall and unusual, sunflowers are fun and easy plants for kids to grow. All they require is a plot of well-drained soil, lots of water and full sunlight. The scientific name of a sunflower is Helianthus, deriving from "helius," which means sun, and "anthus," which means flower.
Sunflowers Grow Tall Fast
Sunflowers are one of the fastest growing plants and they grow tall. Once a seed is planted, an average sunflower plant can emerge and reach a height of up to 8 1/2 feet within six months. The tallest sunflower on record reached a height of 25 feet and 5.4 inches and is listed in the 2004 Guinness Book of World Records.
Sunflowers Follow the Sun
Sunflower leaves are phototropic, which means they follow the sun's rays throughout the day. This allows the sunflower plant to increase the amount of light it takes in, helping the process of photosynthesis, which is how plants convert the energy from sunlight into sugar to help them to grow. The movement of the sunflower plant is easily observable over the course of the day. This phenomenon is known as heliotropism.
Sunflowers Have Large Flower Heads
The largest sunflower head on record grew to a diameter of 32 inches. The average sunflower produces a flowerhead that is 8 to 12 inches across, which is approximately the size of an adult human face. The flowerheads are often so large, they require a support to prevent the plant from breaking under the weight.
Sunflower Heads Are Made of Lots of Flowers
Sunflower plant flowerheads are not just one flower as the name suggests. They are actually comprised of 1,000 to 2,000 individual flowers joined together at a common receptacle (the part of the plant on the flower stalk where flowers attach). The flowers around the circumference of the flowerhead have no stamens or pistils, but the flowers in the rest of the flowerhead do have stamens and pistils.