The Life Cycle of a Sunflower | When Do Sunflowers Bloom?

large yellow sunflower with white background.

Sunflowers are famous for their tall stems and bright, yellow blooms. Aside from the flower’s beauty, its seeds are highly nutritious. Although sunflowers grow best in full sun, they’re a tough plant and can withstand dry climates and most soil types. Beginner and experienced gardeners alike will enjoy the minimal care required to grow a sunflower from a seedling to full maturity.

Sunflowers bloom throughout the summer and early fall. You can read through the various phases of a sunflower’s life cycle to learn how to harvest and use sunflowers in everyday life. Gifting sunflowers, for example, is a great way to show a friend or loved one how much you care. The vibrant color of this well-known plant will surely brighten any room.


Stages of Sunflowers

field of sunflowers with ray of sun.

The sunflower goes through five stages during its life cycle. The germination phase begins the sunflower’s life. The vegetative phase then takes place when the plant grows leaves. Soon after, the reproductive phase occurs, and the bud of the flower forms. The blooming phase then follows, and the flower is fully grown. Once the season is over, you can harvest the seeds for personal use.


Germination Phase

Once you plant your sunflower seeds, the germination phase of the flower’s life cycle will begin. This phase takes up to eight days. During germination, roots will develop from the seed and a shoot will push through the surface of the soil. The shoot is looking for sunlight because all plants need sunlight to grow. Germination usually occurs from mid-April to late-May, depending on when you plant your seeds.


Vegetative Phase

After germination, the vegetative phase of the sunflower’s life cycle occurs. Your plant will still be a seedling for close to 13 days after it breaks through the soil. This initial part of the vegetative phase is called vegetative emergence.

Once the plant forms its first leaf that’s at least four centimeters long, the plant is officially in vegetative stage one (V1). When the plant grows two leaves that are at least four centimeters long, it progresses to vegetative stage two (V2), and so forth.

If you plant your sunflower in April or May, the vegetative phase will occur in May or early June.

green sunflower before it blooms.

Reproductive Phase

The reproductive phase occurs when a bud forms between the plant’s cluster of leaves. The bud may initially have a star-like appearance, but once the reproductive phase is complete, you’ll see your bud transform into the tall stemmed, yellow bloomed plant you know so well.

It takes about thirty days for a sunflower to bloom. The reproductive phase will begin in June and end in July or August.


Blooming Phase

Once your sunflower is in full bloom, you’ll have around 20 days to enjoy the beauty of the flower. The blooming phase provides the opportunity for bees to pollinate the flower and fertilize the seeds. When the back of the sunflower head turns yellow, you’ll know the seeds are ripening.

The blooming phase is the best time to take advantage of your sunflower’s yellow blooms. You can put your flowers in a vase, gift them in a bouquet or make a wreath for the fall.

close up of wilting sunflower.

Harvesting Phase

To harvest the seeds of your sunflower, wait until your sunflower droops and turns brown. Then, cut the stem leaving four inches from the head of the sunflower. You must store the sunflower head upside down in a dry and breathable bag.

Your seeds should be ready to harvest within 110 to 125 days after you planted the flower. This means that if you planted your seeds in May, your sunflower will die in early or mid-August and you should have ready-to-harvest seeds in late-August or September. Because sunflowers are annual plants, they must be replanted year after year.

man grabbing large sunflower with both hands.

Growing Tips for Sunflowers

  • Water sunflowers regularly during the essential growth period.
  • If you plant your sunflowers in poor soil, add a slow-acting fertilizer.
  • Support your sunflowers with staking if they grow over three feet.
  • Use barrier devices around your sunflowers to deter wildlife during harvest time.
  • Check the back of the flower head for yellowing to identify seed ripening.
  • Hang flower heads upside down in a warm, dry place and harvest seeds into a bag.


Ways to Use Sunflowers

When you grow sunflowers in the summer, you can harvest the large blooms and use them in many ways through early fall. You can gift sunflowers to a friend or loved one, decorate your home with their welcoming yellow hue or incorporate them into a wedding arrangement.

smiling man giving women a sunflower.


Gifting sunflowers is the perfect way to show someone you’re thinking of them. Sunflowers symbolize strength, adoration and loyalty, so they’ll have sentimental meaning to friends, family and romantic partners alike. There’s no other plant that can brighten someone’s day quite as easily as a sunflower.

tray with coffee and brownie on table next to sunflowers.


Sunflowers are commonly used in fall decor, such as wreaths and fall bouquets. Their bright yellow tone goes well with the deep browns and oranges of fall. You can incorporate sunflowers into your table arrangement, display them on your mantel or welcome guests into your home by placing them outside your front door.

bride in white dress holding bouquet of sunflowers.


If you plan to have a rustic or outdoor wedding, sunflowers can be an excellent addition to your bouquet. The flowers will make your bouquet pop as you walk down the aisle, and they’ll bring a natural element to your ceremony. Using sunflowers for your wedding bouquet will make your special day memorable to all who attend.

Watching a sunflower grow from a seedling to full maturity is a rewarding experience. The life cycle of the sunflower will teach you patience and proper maintenance of a plant. Once the flower reaches full bloom, you can gift your sunflowers and decorate your home with them. Then, you can harvest the seeds and begin the process again next year.