Giant sunflowers

Giant sunflowers (PublicDomainPictures.net)

Love them, love them not: Sunflowers (genus Helianthus) are part of the daisy (Asteraceae) family. Fear of sunflowers is called helianthophobia. Here are some fun facts, followed by a quiz.

Homegrown goodness: Sunflowers are native to North America, where they were used for food, healing, oils and dyes as early as 3000 BC.

HEAL-ianthus: Native Americans and others have long used the sunflower medicinally. The Cherokees used it to treat kidney problems; the Dakotas, chest pains and lung ailments. Others have used it to treat high fevers, sores and swellings, as well as snake and spider bites.

Super sprout: All of that Vitamin D from the sun does a plant good. The tallest sunflower on record was 30 feet, 1 inch. Even non-champions can grow 8–12 feet in as few as six months.

Thin-leaved sunflower

Thin-leaved sunflower (Fritz Flohr Reynolds/CC BY-SA 3.0)

Here comes the sun: Young sunflower blossoms face east in the morning, then follow the sun as the Earth rotates throughout the day. This behavior, called heliotropism, even takes place on cloudy days and will continue until the stem stiffens to bear the heavy load of growing seeds. Mature flower heads often face east, and these plants can attract five times as many pollinators as westward-facing ones because they warm up more quickly.

That’s sun math! A sunflower can produce 1,000–2,000 seeds. The seeds in the middle are arranged in the Fibonacci sequence (1, 2, 3, 5, 8, 13, 21…), in which each number is the sum of the two that precede it.

Bird grub to dirt scrub: Learn how to harvest sunflower seeds for birds and use what’s left of the flower head as a scrubber for grungy jobs at this web site.

Soil soother: Sunflowers can help remove toxins, including lead, arsenic and uranium, from the soil. They were used after the nuclear disasters at Fukushima and Chernobyl to absorb strontium. The fast-growing plants quickly collect the contaminants in their leaves and stems in concentrations that are much greater than the surrounding soil. Thus, the low concentration of radioactive isotopes in a large area of soil is transferred in high concentration to a plant that can be disposed of and replaced. (The absorption process slows down once flowers start appearing, so the plant is quickly harvested and disposed of before birds can eat the radioactive seeds.)

Swamp sunflower

Swamp sunflower (Eric Hunt/CC BY-SA 4.0)

Mighty small flowers: The sunflower is a composite flower that consists of two florets. The yellow petal-like ring is made up of sterile ray florets. The brown center, depending on the species, can consist of thousands of brown seed-producing disc florets. Each produces one seed that is pollinated by insects or the wind. Should these fail, the flower will self-pollinate by twisting its stigma to reach its own pollen.

Test your knowledge of sunflowers with this quiz. Just match the flower to its description. Answers are below.

  •  Common sunflower (Helianthus annuus)
  • Common sneezeweed (Helenium autumnale)
  • Jerusalem artichoke (Helianthus tuberosus)
  • Swamp sunflower (Helianthus angustifolius)
  • Thinleaf sunflower (Helianthus decapetalus)
Sneezeweed

Sneezeweed (Kurt Stueber/GFDL)

 1.  Forget sunflower seeds and try my tubers boiled, roasted or raw! I taste like a nutty potato but lack the starch. The Italian word, girasole, which means “turning to the sun,” was used to describe me. Its mispronunciation led to my more exotic name. My 3-inch flowers grow on stalks 5–10 feet tall from July to September. I am found in sunny, disturbed areas with moist soil.

2. Songbirds, ruffed grouse and pollinators love me! I am a host plant for the silvery checkerspot butterfly, a species of special concern. I can grow up to 5 feet tall and just one of me grows three to 16 flower heads 1–3 inch wide. I start to blossom in September and don’t stop until the first frost. I grow in wet areas of the Atlantic Coastal Plain.

3. My ancestors were domesticated 3,000 years ago by natives in Western North America. Over time, they increased the size of our seeds by 1,000%. As word of our nutritious seeds and oil and our dye and medicinal properties spread, we were carried eastward and are now found in all of the contiguous United States. We can grow up to 12 feet tall and produce flower heads up to 6 inches wide.

4. Muskrats eat my leaves and use my stems to build their lodges. My scientific name announces that I have 10 petals, but here’s the truth: I have 8–12 yellow ray florets; my petals are on the 21-50 brown disc flowers in my center. I grow about 2 feet tall and bloom in woods, floodplain forests and riverbanks from August to October.

5. Pollen allergies? Quite the opposite! My leaves were dried and made into snuff to help the body expel evil spirits. I have 2-inch flower heads and grow in clumps 3–5 feet tall in moist woods or banks from August to October.

ANSWERS

  1. Jerusalem artichoke
  2. Swamp sunflower
  3. Common sunflower  
  4. Thinleaf sunflower
  5. Common sneezeweed

Kathleen Gaskell is the Bay Journal's copy and layout editor and author of the Chesapeake Challenge. Contact Kathleen at kgaskell@bayjournal.com.

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