A sunflower head is in full bloom. Submitted Photo

If you are looking for an annual flower that brings color and cheer to your garden while providing a food source for wildlife and humans, look no further than the sunflower (Helianthus annuus).

Sunflowers are in the family Asteraceae and are one of the only plants native to North America to become a worldwide crop of economic importance. They have been grown in the Midwestern United States for over 2,000 years and are believed to have originated in Arizona and New Mexico.

In the 1500s, they were brought to Europe and were grown as an ornamental flower. It wasn’t until the 1800s that sunflowers were grown to produce sunflower oil. Russia was a leader in growing sunflowers for their oil, and by the early 1900s, sunflowers had become a major crop in Russia.

Russian sunflower breeders focused on increasing the oil content in the seeds, and popular cultivars such as “Mammoth Russian” (Helianthus annuus “Russian Mammoth”) were introduced to the United States. Today, there are over one million acres of sunflowers grown in the United States for sunflower oil.

The classic image of a sunflower is a large yellow flower with a dark center, but what looks to be one large flower is a composite of small, individual flowers. The “center” of a sunflower is made of hundreds of tiny disc flowers called florets. The “petals” of a sunflower are individual flowers called ray flowers, which serve as protection for the center florets from weather and pests.

Another interesting trait of sunflowers is heliotropism, the ability to follow the sun during the day so the plant can absorb as much sunlight as possible.

As a sunflower matures, gardeners will notice the immature flower head slowly change position as it tracks the sun until it faces west at the end of the day. During the night, the flower head will move back so it faces east when the sun rises.

Sunflowers move their flower heads during the day by growing a bit more quickly on the east side of the stem. This moves the flower head to the west. At night, the opposite happens when the west side of the stem grows more quickly, so the flower head will be facing east by sunrise.

As the flower head reaches maturity and is ready to open, the stem will stiffen, and the flower will permanently face east. Facing east allows the sunflower to warm up quickly in the morning, which attracts more pollinators. When blooming, sunflowers use their internal circadian clock to coordinate the opening of their florets with the sunrise.

A Teddy Bear sunflower is visited by a bumblebee. Submitted Photo

Sunflowers are an interesting, fast-growing, low-maintenance addition to the garden. They do well in a wide range of soil types and can even tolerate clay loam soil.

As a bonus, sunflowers can help improve soil quality due to their deep taproot. They require full sun and grow best in well-drained soil. Sunflowers are easy to grow from seed.

After the threat of frost is over, plant the seeds directly into the soil in a sunny area of your garden. The bloom of a sunflower attracts numerous pollinators, including bees, beetles and butterflies. After the florets have been pollinated and seed production begins, gardeners will see other wildlife come to their sunflowers for food.

Squirrels and birds often visit the flower’s seed head, which can be problematic for gardeners who plan to save their sunflower seeds for future eating or planting. While there is no foolproof method to protect the seeds from wildlife, harvesting the seeds before them drying out can be helpful.

When the sunflower head begins to droop down and the back of the flower turns a greenish-yellow color, they are ready to harvest. Cut the seed heads off with about one foot of the stem still attached. Hang the seed heads in a warm, dry, rodent-free place that is well-ventilated for several weeks. Once the seed heads are completely dry, the seeds can be collected by rubbing the seeds off with your hands.

A developing sunflower head looks like this. Submitted Photo

One of the best features of sunflowers is their variety of colors and sizes. There is truly a sunflower for every size garden, including container gardens. Sunflowers can grow as either a single-stem plant (one flower per plant) or a multibranched plant (multiple flowers per plant).

Multibranched varieties tend to need more space, so plant them 18 to 24 inches apart. If you have a large garden and would like to eat the seeds, try a cultivar of giant sunflowers such as “Mammoth Russian,” “American Giant” (Helianthus annuus “American Giant”) or “Lemon Queen” (Helianthus annuus “Lemon Queen”). These varieties will grow to around 12 feet tall and have very large flower heads that may require staking.

Semi-dwarf cultivars are a bit smaller, growing between 3 and 8 feet tall. They usually do not require staking and work well for most home gardens. Semi-dwarf cultivars include “Italian White” (Helianthus dibilis “Italian White”), “Fire Catcher” (Helianthus annuus “Fire Catcher”) and “Moulin Rouge” (Helianthus annuus “Moulin Rouge”). Dwarf sunflower cultivars grow from anywhere between 6 inches to 3 feet tall, making them perfect for gardens with limited space or container gardens. The cultivars “Teddy Bear” (Helianthus annuus “Teddy Bear”), “Ms Mars” (Helianthus annuus “Ms Mars”) and “Sunray Yellow” (Helianthus annuus “Dwarf Sunray Yellow”) will bring a pop of cheer to your small garden.

Sunflowers come in yellow as well as a variety of colors including white, deep red and bi-colored. To bring sunflowers of different colors to your garden, try burgundy “Prado Red” (Helianthus annuus “Prado Red”), and bi-colored “Indian Blanket” (Helianthus annuus “Indian Blanket”).

Variety also can be found in sunflowers with double flowers or semidouble flowers. These cultivars are good to use as cut flowers because the double flowers help keep pollen from dispersing but are not attractive to pollinators. “Teddy Bear” produces fluffy double flowers, while “Tiger Eye” (Helianthus annuus “Tiger Eye”) produces semidouble flowers with a fluffy, central cluster surrounded by ray flowers.

If you plan to use sunflowers for flower arrangements, consider using a pollenless hybrid such as “Sunbeam” (Helianthus annuus “Sunbeam”). If you are planting sunflowers as part of a pollinator garden, check to make sure you are not buying a double flower or pollenless variety.

In 2023, Penn State Extension started a trial garden in Western Pennsylvania to grow sunflowers as a crop. This trial is based in northern Indiana County and takes place on a farm with a long-standing history of field crop production. To learn about this trial, visit these links: extension.psu.edu/sunflower-chronicles-part-1; extension.psu.edu/sunflower-chronicles-part-2-progress-and-problems; and extension.psu.edu/sunflower-chronicles-part-3-sunsetting-sunflowersfor-2023.

To learn more about sunflowers or to find out what variety might be right for your garden, call the Penn State Extension Master Gardeners of Butler County via the Garden Hotline at 724-287-4761, ext. 7, or email butlermg@psu.edu.

Amy Cirelli is a Penn State Extension Master Gardener of Butler County.

Amy Cirelli