(888) 349-0605 M-F: 10-7 EST

Complete Guide to Plant, Grow, and Care for Sunflowers

Woman with Sunflowers

A favorite of kids! Home flower gardeners are growing sunflowers from seed for their rich colors, large blooms and dazzling golden heads. Easy to start indoors, they are available in sizes ranging from miniatures — good for edging — to over 10 feet tall with 2-foot diameter blooms. All have big, lusciously colored blossoms that vary from the traditional yellow and orange to cream and tan.

Sunflower seeds germinate quickly and can be an adventure in tiny to towering plants. Best of all, they provide plenty of seeds to harvest at the end of the season, making them the ideal plant for children.

Plant sunflowers in full sun and in rich soil on the north side of the garden so they won’t shade other plants. A hardy annual that will probably volunteer next year, thanks to dropped seeds and active birds.

Fun fact: The world’s tallest sunflower was grown by Hans-Peter Schiffer of Germany and measured in at 30-ft 1-in, a Guinness record. He held this record twice previously.

Botanical Name: Helianthus annuus

Common Name: Sunflower, common sunflower

Family: Asteraceae

Plant Type: Annual

Hardiness Zones: 2 to 11 (USDA)

Sun Exposure: Full sun

Soil Type: Well-drained

Soil pH: 6.0 – 7.5 (Slightly acidic to slightly alkaline)

Maturity: 60-95 days from seed to flower

Height: 2 to 10 feet

Spacing: 4 to 12 inches apart in all directions

Bloom Time: Summer, fall

Flower Color: Yellow, red, mahogany, bicolors

Native Area: North America

Quick Guide: Planting, Growing & Caring for Sunflowers

  • Choose from dwarf or giant varieties in an array of yellow, red and orange hues
  • Direct seeding recommended once all danger of frost has passed
  • Needs full sun with average to rich soil that can support strong roots
  • After blooms have passed, let dry and save seeds or leave in garden to feed birds
  • Rarely bothered by pests and diseases
Sunflower Field

Photo Credit: Dreamstime.

Sunflower Plant Care

Sunflowers are heat-tolerant, pest-resistant, and enticing to pollinators and birds, with summer-long blooms of breathtaking yellow.

They typically begin blooming in the middle of summer and can last until the beginning of fall and produce lovely cut flowers and provide food for both people and birds in the form of seeds and oil.

Birds, bees, and butterflies will all appreciate your efforts to bring them in by planting these flowers. Not only are their blooms attractive to pollinators, but the dried seed heads can be left out all winter for the birds to enjoy.

They make great companion plants for your vegetable garden. Sunflower was the fourth sister used by Native Americans alongside corn, beans, and squash.

While annual sunflowers are more common, there are also perennial varieties. These types are great for the flower garden because they come back year after year and provide a constant supply of bright, cheery blooms with minimal effort on your part.

Sunflowers, as was just mentioned, are a great plant to have in your garden if you want to attract local birds. At the end of the growing season, you can harvest your sunflower heads and use some of the seeds to feed the birds during the winter.

If you want to feed birds sunflower seeds, you can do one of two things. The first is to just let the birds eat the sunflower heads. This is the easiest way to do it, but be aware that the birds will probably make a mess when they pull the seeds out of the sunflower head.

Alternately, you may remove the seeds from the head and place them in a bird feeder.

Light

Plant your sunflowers in full sun, or at least six hours of direct sunlight per day, for the best flowering and the most robust stems.

Sunlight exposure will help sunflowers stay straight rather than bending in the direction of the light’s intensity because they are heliotropic which means their flower heads follow the sun.

Soil

Sunflowers can grow in nearly all soil types, including dry, poor soils. However, they thrive in soil that is well-drained and rich in organic matter. They prefer soil that is slightly acidic to slightly alkaline (pH 6.0 to 7.5)

Water

Sunflowers can tolerate dry conditions, but regular watering encourages blooming because flowering frequently declines during dry spells.

The top 1–2 inches of soil should be allowed to dry out in between waterings. If the soil around your sunflowers is dry and the plants are drooping, that usually means they need more water.

Once established, they are drought tolerant. However, deep, regular watering is optimal for their growth and development before, during, and after flowering.

Temperature and Humidity

Sunflowers do best at temperatures between 70 and 78 degrees Fahrenheit. However, t hey can withstand high temperatures as long as their needs for moisture are met.

Sunflowers can tolerate slightly chilly but sunny conditions. They can also withstand high humidity, but they require well-draining soil and adequate air circulation to avoid root rot and other diseases.

Fertilizer

Sunflowers are heavy feeders, so the soil must be nutrient-rich with organic matter or composted manure. Alternately, you could incorporate a slow-release granular fertilizer into your soil around 8 inches deep.

Sunflowers with a cloudy sky

Photo Credit: Dreamstime.

Types of Sunflowers

We’ve all seen beautiful sunflowers that can grow on stalks that go up to eight feet tall. But there are quite a few different varieties that feature other heights and variations. Let’s look at the four most popular ones we recommend you check out:

Mammoth: The traditional giant sunflower is the tall ‘Mammoth’ variety, which can grow to more than 12 feet tall. Its seeds make great snacks and are also good for feeding birds.

Autumn Beauty: Autumn Beauty is one of the most beautiful cultivars. It has many 6-inch flowers in shades of yellow, bronze, and mahogany on stems that can grow up to 7 feet tall and branch out.

Teddy Bear: This small sunflower is ideal for small gardens and containers, standing only 2 to 3 feet tall. The 5-inch, fluffy deep-gold flowers last for days in a vase.

Sunrich Gold: This sunflower variety matures to a height of about 5 feet and bears a single flower between 4 and 6 inches in diameter, making it ideal for use in bouquets and flower arrangements. The large, pollen-free blooms are a rich golden yellow on the outside and a bright green in the middle.

Italian White: The ‘Italian White’ sunflower has a sophisticated appearance in the garden or vase because its large blooms are typical of giant sunflowers while its well-branched, floriferous habit is typical of smaller daisy-formed varieties.

How to Plant and Grow Sunflowers

Site Preparation

Plant sunflowers in full sun and in rich soil on the north side of the garden so they won’t shade other plants (see Springtime Garden Soil Preparation). It is not recommended to plant sunflowers in sandy soil as they need a strong base to support their tall, top-heavy plants.

If you can, plant sunflowers in a place that is protected from strong winds, like near a building or along a fence. Larger varieties are susceptible to becoming top-heavy, and a strong wind can be detrimental.

How to Plant Sunflowers

Sunflowers are very easy to direct-seed. They are an annual flower, which means they only bloom once a year from spring to fall). Therefore, early spring is the ideal time to plant sunflower seeds.

Sow after all danger of frost has passed, about 4 to 12 inches apart with 1/2 inch of soil covering them.

After seeding outdoors, watch for squirrels and birds – they like to steal the freshly planted seeds to supplement their diet. If starting seeds indoors, use CowPots or pots made of newspaper that can be planted directly into the garden.

Once established and healthy, plants will continue growing easily even if left unattended (watch our video Flower Gardening from the Ground Up). Water to keep the soil slightly moist and provide support when plants begin to get top heavy. Leave mature flower heads on the plants to attract birds to your garden.

Consider planting in a circle to make a sunflower house for children or in a row to create a private, gorgeous sunflower hedge.

Seed Saving Instructions

Separate sunflowers by 1/2 mile to ensure pure seed. Harvest the heads when they have completely filled out, have lost all of their petals, and the backs begin to turn brown. Allow to dry in a protected area and then shell by hand.

Common Pests and Plant Diseases for Sunflower Plants

Insects and disease are not typically a problem for sunflowers. Sometimes, a small gray moth may lay its eggs in the flowers. You can pick the worms off the plants.

Additionally, powdery mildew, rust, and downy mildew can affect the plants. Spray with a general garden fungicide if you see signs of fungal diseases early on.

The seeds will attract birds and squirrels. If you want to use the seeds, put up barriers to keep animals away. As seed heads develop and flowers wither, you can cover each one with white polyspun garden fleece.

If you have deer, put up a tall wire fence to keep them away. Deer can be very curious, and they have been known to eat the heads off of young sunflowers.

 

More Flower Guides from Planet Natural:

Begonia: How to Plant, Grow and Care for Begonia Plant

Gladiolus: How to Plant, Grow and Care for Gladiolus Flowers

How to Plant, Grow, and Care for Amaryllis All Year Round

Website | + posts

Eric Vinje founded Planet Natural with his father Wayne in 1991, originally running it as a grasshopper bait mail-order business out of a garage.

Eric is now retired, but is still a renowned gardener known for his expertise in composting, organic gardening and pest control, utilizing pesticide-free options, such as beneficial insects.

Eric believes when you do something good for the environment, the effects will benefit generations to come.