Mid-Atlantic Regional Reports

How to Grow Annual Sunflowers for Pollinators and Wildlife

Easily grown from seed, this symbol of summer is a gift for pollinators, birds, and your garden

A sure sign of summer, sunflowers in bloom mean the warmer months are in full swing and the garden should be reaching its peak. Photo: Jennifer Benner

As we enter the dog days of summer, many of us are buzzing about with trips to the beach, firing up the old grill, and celebrating our country’s independence. In between our attempts to pack as much into the warmer months of the year as we can, consider growing a plant that symbolizes the peak of the season like no other, the sunflower (Helianthus annuus, annual). Though considered in some circles a somewhat pedestrian plant that befits only the beginner gardener, there are many reasons why growing sunflowers are a boon to your garden. Learn all about how and why to grow annual sunflowers below.


Sunflower Basics at a Glance

(Helianthus annuus)

Annual

Light: Minimum 6 hours a day of sunlight

Soil: Well-drained, slightly acidic to somewhat alkaline

Moisture: Deep, regular watering

Fertilizer: Not necessary. Can apply slow-release fertilizer after second set of leaves appear to help growth.

Did you know?

The name “common sunflower” did not come from its sunshiny appearance but the plant’s ability to follow the sun. Young flowers are able to track the sun from east to west daily and reorient themselves every night to greet the sun in the morning. As the inflorescence matures and the floral stems gain rigidity, the sun tracking ceases and the fixed position as maturation occurs is due east. This phenomenon of flower heads following the sun is called heliotropism.


Summer sunflower
Native to North America and Mexico, there are 52 known species of sunflowers. Given their wide distribution and growing range, which is primarily in open lands along roadsides, grasslands, prairies, fallow fields, and woodland edges, they are quite adaptable to a wide range of conditions.  Photo: Fionuala Campion

Grow Sunflowers for Pollinators and Wildlife

Although many assume a sunflower is one large flower, the inflorescence, or flowering structure, of Helianthus annuus is actually a composite of many flowers. This is a telltale trait for the Asteraceae family, to which sunflowers, daisies, aster, and others belong. The composite head is made up of hundreds, or even thousands, of individual tiny disc florets inside a ring of ray florets. The outer ray florets are sterile, but the countless disc florets can all produce a viable seed if properly pollinated. As a result, sunflowers are loved by pollinators due to the high concentration of nectar and pollen provided by the thousands of tiny flowers in a compact space.

One flower, or thousands? What many would think is just the “center” part of one big sunflower bloom is thousands of individual flowers that can each be pollinated and produce a viable seed. Photo: James Johnstone via CC BY 2.0

The bird enthusiast among us may consider growing sunflowers to supplement the fall and winter diets of our feathered friends. Sunflower seeds are extremely nutritious, an excellent source of protein, and high in calories. As birds prepare for fall migration, sunflower seeds can help them build reserves for their long flight. Conversely, those that endure the winter very much appreciate the seed’s high fat content to keep them warm through the colder months. The goldfinch, great spotted woodpecker, house finch, northern cardinal, black-capped chickadee, junco, mourning dove, tufted titmouse, gray catbird, white-breasted nuthatch, and many others favor sunflower seeds as a food source. Learn more about supporting birds in winter.

To mimic the natural seasonality of migration or building up of reserves for the winter, simply leave the mature flower on the stalk and allow birds and other mammals such as squirrels and chipmunks to forage as they see fit. Or, if you would like to supplement feeding throughout the winter, harvest the flower heads as they begin to turn brown and hang them in a dry location for use later. Learn more here.

Also an excellent food source for humans, sunflowers have become a more commonly grown agronomic crop. Thousands of acres are sown yearly to produce sunflower oil as well as roasted seeds. Roasting your own sunflower seeds can make for a healthy and delicious snack or a special handmade gift.

using sunflowers as birdfeeders
Though this drooping, end-of-season sunflower might look a little unsightly and sad, it’s a beautiful bounty for birds and small mammals during a critical time. Photo: Michelle Gervais

Growing Sunflowers from Seed

A relatively quick-to-mature crop, 85–95 days is all that is needed from planting to harvest. To extend the floral display, stagger planting of seeds or seedlings every 2–3 weeks.

sunflower seedlings
Sunflowers can be direct sown into your garden or started indoors for earlier flowering or a succession of blooms. Photo: Jennifer Benner

How to Direct Sow Sunflowers:

  • As an annual, the simplest way to establish a healthy patch is to direct sow seeds after the threat of frost has passed, sowing each seed 1–2 inches deep and 6″ apart.
  • Depending on the mature size of the cultivar you choose, you may need to thin the seedlings to avoid overcrowding.
  • If planting in rows, allow 2–3 feet between each plant.

How to Start Sunflower Seeds Indoors:

  • Starting seeds indoors to encourage earlier flowering once planted outside is also a viable option.
  • If you do start seeds indoors, please remember to slowly harden off your tender seedlings before planting in the garden. This can be done by placing the seedlings outside for a few hours, preferably in an indirect light environment, and gradually increasing outdoor time over several days to a week.

What Sunflowers Need to Grow:

  • A minimum of 6 hours of direct sunlight is ideal, but they will relish as much sun as can be provided.
  • After young plants produce a second set of leaves, I recommend applying a slow-release organic fertilizer to support their rapid growth.

Sunflower Pests to Watch For:

  • If provided with proper growing conditions, pests and disease generally are not a major concern. However, deer do quite enjoy young, tender plants, so protection in the form of repellents or caging may be needed if deer populations are high in your neighborhood.

The Best Sunflower Varieties to Try

A Great Dwarf Sunflower Variety

  1. ‘Teddy Bear’
  • Grows 18-24″ tall with a bushy habit
  • Blooms have a unique, unusual texture
  • Many blooms on one plant

‘Teddy Bear’ sunflower
A delectable dwarf variety with super-unique double blooms, ‘Teddy Bear’ is an excellent pick for smaller gardens and patio containers. Photo: Dawnn McWatters

The Best Sunflower for Wildlife

  1. ‘Black Oil’
  • Yellow petal florets with golden brown centers that turn black as seeds mature
  • Seeds contain more oil than most other sunflowers
  • Excellent food source for birds

Black oil sunflower in field
A field of ‘Black oil’ sunflowers. Photo: via CC BY 2.0

An Unusual Color in a Sunflower

  1. ‘Black Beauty’
  • Outer petals that are deep red in the center with softer red at the tips
  • Black center florets and dark green foliage
  • Multiflowered/multibranched habit
  • Long flowering period

Sunflower 'Black Beauty'
A vibrant red annual sunflower looks beautiful when autumn comes. Photo: Swallowtail Garden Seeds by CC BY 2.0

For the True Sunflower Enthusiast

  1. ‘Mammoth Grey Stripe’
  • Classic giant sunflower, as the name implies
  • Can grow up to 12′ tall with 10″ blooms
  • Large blooms have the potential to produce a large number of seeds

'Mammoth grey stripe' sunflower
‘Mammoth grey stripe’ is a large variety of sunflower that towers over 12 feet tall.

A Sunflower for a Paler Garden Palette

5. ‘Vanilla Ice’

  • Grows to 5′ tall
  • 3″–5″ wide, creamy, light yellow flowers
  • Flowers and buds are edible and can be added to summer salads for a pop of color

Sunflower 'Vanilla Ice'
‘Vanilla ice’ offers a lighter yellow for use in the garden and bouquets. Photo: Agnieszka Kwiecień, Nova, CC BY-SA 4.0, via Wikimedia Commons

 

 


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Adam Glas is a garden supervisor and rosarian at the Scott Arboretum of Swarthmore College in Swarthmore, Pennsylvania.

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