Sunflower (Helianthus annuus)

Plant, Grow and Care

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Plant - Grow - Care for Sunflowers:

Sunflowers are one of the easiest flowers to grow with children.
They are fast growers and disease resistance.
To me, its the heliotropism behavior that makes sunflowers fascinating to teach, watch and learn.

So, what is "Sunflower heliotropism"?

Heliotropism is the natural behavior of sunflowers to follow the movement of the sun throughout the day. In the morning a young sunflower starts facing East, by the afternoon it will facing West and back to facing East by morning and waits for the sunrise.

The word "heliotropism" comes from the Greek words "helios" (meaning sun) and "tropos" (meaning turning), and it describes the phenomenon of plants orienting themselves in response to the sun's position in the sky by maximizing their exposure to sunlight, which is crucial for photosynthesis.

As sunflowers mature and begins to produce flowers, the heliotropic response diminishes.
By then the mature sunflower has "been there, done that" and leaves it for the young ones. :)
So, at this point, the sunflower heads generally faces eastward to maximize exposure to the morning sun, which helps attract pollinators.
More information on "heliotropism" from Wikipedia on

Sunflower Varieties:

  1. Giant Sunflowers
  2. Dwarf Sunflowers
  3. Multi-stem Sunflowers
  4. Pollen-free Sunflowers
Most of the time, I just buy a packet of "Mixed Sunflowers" seeds and you never know what you get.
Last year it came with a "plum" sunflower seed. Not sure what to think of that colour yet.
My sister is the "Sunflower Queen" and she shared some of her seeds with me.

Here are Varieties of Sunflower that I have that my sister sent me:

Giant Sunflowers: These varieties, such as 'Russian Mammoth' or 'Mammoth Grey Stripe,' are known for their immense size and can grow up to 15 feet tall and flower heads can be as big as 1 foot across.

Dwarf Sunflowers: They typically reach a height of 1-1/2 to 2 feet and produce smaller flower heads, which I find just the right size for cut flowers and flower pots.

Multi-Stem Sunflowers: Varieties like 'Italian White' or 'Velvet Queen' produce multiple flower stems from a single plant. They work well as a cut flower and creating floral arrangements.

Pollen-Free Sunflowers: This one is new to me. 'Sunrich Orange' or 'Sunbright Supreme,' produces beautiful flowers without the pollen that triggers allergic reactions.

Planting Sunflowers:

Sunflowers are relatively easy to grow and can be directly sown into the ground or started indoors before transplanting.

I have tried both methods:
Self-seeding: Is the best method for me. The seeds survives our cold winters and they are up and growing before I can even work the soil in the spring. However they self-seed where I don't want them. Those I just pull them out.
Direct sow: It was ok. I have to cover the seeds until they start germinating, because the wildlife is hungry at that time of the year.
Sowing indoors: They get leggy and it doesn't do as well as the self-seeders or direct sow.

Choosing the Right Location: Sunflowers thrive in full sun. Select a location in your garden that receives at least six to eight hours of direct sunlight each day that is on the North side of the garden. Therefore, the tall plants won't shade your other vegetables. Sunflowers are not fussy about soil.

Preparing the Soil: Loosen the soil. Incorporate organic matter like compost to enrich the soil.

Direct Sowing: For direct sowing, wait until after the last frost date when the soil has warmed up. Dig a hole about 1 inch deep and place one or two seeds in each hole. Space the holes 6" apart and thin large types to 1-1/2 feet and dwarf and medium-size cultivars to 1 foot apart. Water well after sowing.
Once the seedlings have emerged, thin them to leave only the strongest plant per hole. Apply a layer of mulch around the plants to help retain moisture and suppress weeds.

Watering and Care: Sunflowers are drought-resistant, but they will grow better with regular watering from the time the flowers starts to develop until they're mature.

Providing Support: Depends on the variety or if they are falling over due to wind or heavy flower heads. I usually have extra bamboo poles, just in case.

Fertilizing: Sunflowers generally do not require any fertilizer. However, you can use a diluted liquid fertilizer during the growing season if necessary.

Sunflower Care and Maintenance:

Mulching: Apply 3-4 inches layer of mulch to help conserve moisture, suppress weeds and maintain a stable soil temperature.

Pest and Disease Management: Sunflowers are generally resistant to pests and diseases. Sometimes powdery mildew. I just leave it, because it's almost time to cut them down anyway.

Protect your seeds from birds: Cover the flowers with, cheesecloth and mesh bags. My favorite: knee-high stockings or pantyhose. :)
If you have squirrels - nothing can stop them. They will break everything trying.

Harvesting Seeds: If you're growing sunflowers for their seeds, monitor the flower heads as they mature. When the back of the flower head turns yellow and the seeds appear plump, it's time to harvest. Cut the flower heads, leaving about 2 feet of the stem attached. Hang them upside down in a dry and well-ventilated area to dry completely. Once dry, rub the seeds out of the flower head and store them in a cool, dry place.

Sunflowers to eat: Soak over night in strong salt water or just water. Drain, spread on a shallow baking sheet and roast for 3 hours at 200°F. or until crisp.

Did you know?

Sunflowers have an amazing variety of uses. I use mine for cut flowers and bird seed.
However, they also make a good fodder for poultry and livestock.
Dyes come from the sunflower petals and paper can be made from the stock pith.
Sunflower-seed oil is used in cooking, soaps and cosmetics.
In the garden, you can grow sunflowers as windbreaks, privacy screens or living supports for pole beans. I also use them on the edge of my vegetable and flower beds for protecting my crops when I'm dragging my hose around for watering. :)

Direct Sow
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