Gardening Flowers Annuals How to Plant and Grow Annual Sunflower Add color and whimsy to almost any garden space with these low-maintenance, fast-growing, sun-loving blooms. By Viveka Neveln Viveka Neveln Viveka Neveln is the Garden Editor at BHG and a degreed horticulturist with broad gardening expertise earned over 3+ decades of practice and study. She has more than 20 years of experience writing and editing for both print and digital media. Learn about BHG's Editorial Process Updated on September 20, 2023 In This Article View All In This Article Where to Plant Planting Tips Care Propagation Pests and Problems Types Companion Plants FAQ Trending Videos Close this video player Sunflowers (Helianthus annuus) are heralds of summer, but they are also known for being easy to grow, heat-tolerant, pest-resistant, and quick to stretch as tall as the average adult. Native to North America, annual sunflowers can grow almost anywhere—so it’s not uncommon to find them growing along roadways, fences, and fields across the country. Depending on your climate, annual sunflowers may begin blooming in late spring or early summer and continue until early fall. Flowers typically arrive with bright yellow petals and yellow, orange, or brown centers, but you can also find blooms with petals in red, orange, maroon, and chocolate brown. Sunflowers make stunning cut flowers, but will attract bees, butterflies, and birds to your yard for as long as they are left on the stalk. Sunflower Overview Genus Name Helianthus annuus Common Name Sunflower Plant Type Annual Light Sun Height 1 to 10 feet Width 1 to 3 feet Flower Color Orange, Purple, Red, Yellow Foliage Color Blue/Green, Chartreuse/Gold Season Features Fall Bloom, Summer Bloom Special Features Attracts Birds, Cut Flowers, Good for Containers, Low Maintenance Zones 10, 11, 2, 3, 4, 5, 6, 7, 8, 9 Propagation Seed Problem Solvers Drought Tolerant Where to Plant Annual Sunflower A cinch to grow from seed, sunflowers can be planted almost anywhere. For the cost of a packet of seeds, you can enjoy a bevy of these summertime beauties in the cutting garden, alongside a lackluster garage wall, near a mailbox, at the back of a cottage garden, or near your front door. Basically, if your garden space has full sun and well-drained soil, you can grow sunflowers. Use small varieties in landscape beds for a touch of whimsy in midsummer. Dress up a drab fence with three rows of sunflowers, beginning with a knee-high variety (like 'Sunspot’ dwarf sunflowers) up front, a midsize variety (like ‘Taiyo’) in the middle, and a mammoth variety (like 'Mongolian Giant') next to the fence. It should be noted that Helianthus annuus is considered an invasive weed in parts of Nevada. In Iowa, the common sunflower is classified as a noxious weed. Before planting in these areas check with your local garden extension service office or cooperative. How and When to Plant Annual Sunflower Start sunflower plants from seed indoors six to eight weeks before the last frost or sow them directly in the garden once soil has warmed in spring. In the garden, plant your sunflower seeds about 1 inch deep and about 6 inches apart. Water as needed to keep the soil moist. Seedlings should emerge in about 7 to 10 days (but may take as long as 2 weeks). When seedlings are about 3 inches tall, thin them so there is one plant every 12 to 18 inches. Well-spaced seedlings are key to strong, upright sunflowers later in the season. Plants will develop weak and wobbly stems if they grow too closely together, or if they don't get enough light. If you plant seeds every two weeks or so beginning in late spring, you can enjoy fresh crops of annual sunflowers until the first frost. Annual Sunflower Care Tips Sunflowers are easy to grow in almost any garden and come in a wide variety of sizes and colors. A quick look at the seed rack at your local nursery or an online search will reveal a host of colorful sunflowers, ranging from petite 2-foot-tall varieties to giants that stand 10 feet tall or more. Light As the name implies, annual sunflowers thrive in full sun and will fare best if they get at least 6 to 8 hours of direct sunlight each day. In fact, studies have shown that growing sunflowers will turn to track the movement of the sun throughout the day. Mature sunflowers are likely to settle with their blooms facing east. If you choose to stake your sunflowers, avoid doing so before it becomes necessary (perhaps when they start to bend) and try not to stake the stalks so tightly that the stake restricts the natural movement of the sunflower. Soil and Water Sunflowers prefer moist, well-draining soil with a slightly acidic to alkaline soil pH (6.0 to 7.5) but are adaptable to almost any soil conditions. In fact, the long tap roots of the sunflower may improve soil conditions in locations where they are planted. Annual sunflowers are also drought-tolerant but will bloom better if watered regularly. When your sunflower is young, water it deeply about once a week—or less if the weather is wet. This schedule will encourage your plant’s roots to grow healthy and strong. Once it is mature, you can water your sunflower just whenever the top 2 inches of soil feel dry. Be mindful of overwatering as that can lead to root rot and other problems. Temperature and Humidity Sunflowers are somewhat cold tolerant, but don’t fare well in frost conditions. For that reason, it’s best to plant them only after the danger of frost has passed. The sweet spot for sunflowers is when temperatures stay between 68- and 80-degrees Fahrenheit. The summer-loving annuals are tolerant of the season’s highest temperatures, but when the thermometer tips above 95°F, you may notice some wilting and curling of the leaves and petals. Sunflowers can also tolerate high humidity levels if they are planted in well-draining soil and have plenty of air circulation to ward off root rot and other fungal diseases. Fertilizer Annual sunflowers like nutrient-rich soil and a springtime application of slow-release fertilizer that contains nitrogen, phosphorus, and potassium can help encourage blooms and healthy growth. If your soil is already rich and loamy, you may not need to supplement it with fertilizer at all. If you choose to use fertilizer, apply it several inches away from the base of the plant and follow the label’s instructions to avoid overfeeding. Excessive or incorrect use of fertilizer may cause the plant’s stalks to droop or break. Pruning Annual sunflowers do not need pruning, but you can deadhead the blooms (ideally before they produce seeds) if you do not want self-seeding to occur. If you wish to cut sunflowers for bouquets, cut them early in the morning and before the petals have fully opened from the face of the bloom. Cut the stems at a 45-degree angle and make sure each bloom has approximately 24 inches of stem. Place your cut blooms in a bucket of hot water (yes, hot) and keep them in indirect light for several hours while they soak up the water. After 6 to 24 hours, you can move them to your bouquet or arrangement. Dwarf annual sunflowers, however, may benefit from being pinched back at the start of the growing season before flower buds emerge. This will help persuade lush growth. You can also deadhead the blooms of the dwarf annuals after they fade to encourage more blossoms. Potting and Repotting Sunflowers make great container plants—especially the dwarf varieties. You can also grow the midsize (3 to 6 foot) sunflowers in containers, but you will need a container large enough to accommodate both the mature height of the plant and the long tap root. For midsize sunflowers, that means selecting a pot that is at least 10 to 12 inches in diameter (or a 7-to-10-gallon pot). Dwarf varieties should fare well in a 6-inch pot (for a single plant) or a gallon size container (for two to three plants). Choose a pot that has ample drainage and is made from a material that will help the soil retain its moisture—like plastic, metal, or glazed terra-cotta. Fill the container two-thirds of the way with a rich, loamy potting mix, moisten the soil, and add your seeds. If you are planting multiple sunflowers, place the seeds approximately 4 inches apart. Cover the seeds with more potting mix, tamp the soil down, and water again. Place your container in an area that is protected from strong winds and receives 6 to 8 hours of full sunlight each day. Keep the soil evenly moist, but not wet, and the seeds should begin to germinate in 7 to 14 days. Annual sunflowers dislike having their roots disturbed, so it’s best to avoid transplanting or repotting them, if possible. If you must transplant yours, do it in mid to late spring (before the growth season is in full swing) to minimize transplant shock. How to Propagate Annual Sunflower The easiest way to propagate annual sunflowers is via seed. To harvest seeds from a mature sunflower plant, cut the whole flowerhead from its stalk (with approximately 12 inches of stem) and wrap it in cheesecloth or a mesh bag to catch any errant seeds. Hang the flower head in a warm, dry place away from hungry squirrels and insects and allow the flowerhead to dry completely. You can also place a mesh bag over the flowerhead while it is still on the stalk and leave it to dry in place. If you are not direct-sowing your seeds, save them in a cool, dry location to plant the following spring. Pests and Problems Sunflowers are susceptible to issues with sunflower moths. These small, gray pests lay eggs on the sunflower that develop into larvae which feed on the flowerheads and tunnel through seeds. Otherwise, insect-type pests tend to leave sunflowers alone. Birds, squirrels, and other small rodents, however, are known to be a nuisance—especially while you are trying to germinate new plants. Use a layer of netting—like cheesecloth, garden fleece, or mesh bags—to deter seed-thieving critters from disrupting your crops. Deer are also prone to nibbling on the new and established flower heads. Use deer-resistant fencing or plant a barrier of deer-resistant shrubs to keep them at bay. Sunflowers can also have issues with root rot, powdery mildew, downy mildew, and rust. Types of Annual Sunflower 'Autumn Beauty' Sunflower Bill Stites This Helianthus variety bears large reddish-orange flowers on 5-foot-tall plants in zones 2-11. 'Evening Sun' Sunflower Bill Stites Helianthus 'Evening Sun' bears reddish-mahogany flowers on large, 6- to 8-foot-tall plants in zones 2-11. 'Gloriosa' Sunflower This type of Helianthus bears large reddish-orange flowers on 8-foot-tall plants with multiple branches in zones 3-10. 'Italian White' Sunflower Bill Stites Helianthus 'Italian White' bears creamy-white flowers on 5-foot-tall plants in zones 4-9. 'Music Box' Dwarf Sunflower Charles Mann This dwarf Helianthus cultivar bears red and yellow flowers on 3-foot-tall plants in zones 3-10. Sunbeam Sunflower Bill Stites Helianthus 'Sunbeam' bears pollenless yellow flowers with yellow centers on 6-foot-tall plants in zones 3-11. 'Teddy Bear' Double Sunflower Jane Booth Vollers This Helianthus variety bears interesting double yellow flowers on dwarf 3-foot-tall plants. 'Velvet Queen' Sunflower Alise O'Brien Helianthus 'Velvet Queen' bears rich, rusty-red flowers shaded with bronze on plants that grow 5 feet tall in zones 2-11. Companion Plants for Annual Sunflower Castor Bean Eric Roth Plant a castor bean and then stand back. This is one of the fastest-growing, giant annuals in the garden, rivaled only perhaps by giant sunflowers. By midsummer, you'll have a huge (it can hit up to 20 feet) tropical plant sporting burgundy foliage. It's a great plant to grow with kids. Be careful, though. The seeds are extremely toxic. Wait to plant it outdoors after all danger of frost has passed; castor bean hates cool weather and won't grow well until temperatures heat up in summer. Corn Kritsada Panichgul Corn and sunflowers grow surprisingly well together—especially since sunflowers tend to attract ladybugs which feed on corn-damaging pests like aphids, mites, and fruit flies. You will often find fields of corn surrounded by rows of sunflowers for this very reason. That, and because birds are less likely to attack corn plants when there are tasty sunflower seeds to eat nearby. 10 Best Companion Plants for Corn Kiss-Me-Over-the-Garden-Gate Eric Roth Try this delightful flower to grow something different and striking in your garden. You don't see this old-fashioned plant as often as you used to, but when you do it is spectacular. Chains of delicate pink flowers hang down from tall stems that can reach 12 (or more) feet tall on this fast-growing annual. It's great for creating a quick privacy screen or making a bold statement in big containers. Kiss-me-over-the-garden-gate can, however, self-seed in the garden. Nasturtiums Peter Krumhardt Like sunflowers, nasturtiums grow best in full sun and are excellent at suppressing weeds and attracting pollinators. The fast-growing annuals (or perennials in zones 9-11) offer pretty lotus-like foliage even when the bright orange, pink, red, white, and yellow blooms are not in season. You can find climbing, trailing, or mounding cultivars that work well in garden beds or containers. Nasturtiums also perform well as edging plants and can be used to surround vegetable gardens as a natural pest deterrent. Zinnia Peter Krumhardt Want fast color for just pennies? Plant zinnias! A packet of seeds will fill an area with gorgeous flowers in an amazing array of shapes and colors—even green! And it will happen in just weeks. There are countless types of zinnias, including dwarf, tall, quill-leaf cactus, spider, and multicolor types. You can also find special seed blends for cutting, for attracting butterflies, and more. Zinnias are so highly attractive to butterflies that you can count on having these fluttering guests dining in your garden every afternoon. To maximize butterfly visitation, plant lots of tall, red or hot pink zinnias in a large patch. 'Big Red' is especially nice for this and the flowers are excellent for cutting. Zinnias grow quickly from seed sown right in the ground and fare best in full sun with dry to well-drained soil. Frequently Asked Questions Can I harvest my sunflower seeds to eat? Yes, but not all varieties will produce viable seeds. There are a number of sterile cultivars that have been developed to produce long-lasting blooms, but no seeds. These cultivars are commonly used in the cut flower industry. The large-headed varieties (like 'Giant Grey Stripe', ‘Titan’, and 'Mammoth Russian') tend to be more successful at producing seeds. These sunflowers form a single large flower head atop a stem that may reach 10 feet or more. To harvest, allow the seed heads of these varieties to start to dry and turn yellow before cutting the head off the stalk. Store the head in a dry, well-ventilated place where the seeds can fully mature. Seeds are ready to store or eat when the disk at the back of the flower has turned dark brown. Is it possible to grow mammoth sunflowers in containers? Technically, yes. It is possible. If you choose to, be aware that giant cultivars (like ‘Mongolian’ Giant) can grow as tall as 10 feet with tap roots that extend as far as 6 feet deep. To accommodate a plant this size, you will need a very large (10-gallon or larger) container and a system of support to keep it from toppling over. How can I tell the difference between annual and perennial sunflowers? Look at the seed label (if you have it). While the botanical name Helianthus can refer to either annuals or perennials, annual sunflowers are further defined by the latter half of their botanical name, annuus (which means annual). If you don’t have the seed or plant label, you can spot the difference by noting the growth habit and shape of your plants. Annual sunflowers tend to bloom a little later in the spring and will grow much faster than perennials. Annuals also grow their flowers atop one main stalk as opposed to forming clumps of stems and blossoms. Finally, annuals have a deep taproots to support their tall stalks while perennial sunflowers develop an intricate system of tubers and rhizomes that helps them survive the winter. Can planting sunflowers improve the health of my soil? Yes. Sunflowers have deep, sturdy tap roots that can break up compacted soil, improve the soil structure, and extract heavy metals (like lead, zinc, chromium, cadmium, copper, arsenic, and manganese) from the soil. Sunflowers can also deter weeds as their seeds create an allelopathic effect—which is basically a biological chemical reaction that explains why some plants won’t grow around others. This effect has downsides, too. Since sunflowers are allelopathic, they can deter desired plants (like grass) from growing nearby. Potatoes and pole beans are also susceptible to the allelopathic effect of sunflowers, so avoid planting them in close proximity. Peas and sweet peas, however, are okay to grow as a companion plant to sunflowers. Was this page helpful? Thanks for your feedback! Tell us why! Other Submit Sources Better Homes & Gardens is committed to using high-quality, reputable sources—including peer-reviewed studies—to support the facts in our articles. Read about our editorial policies and standards to learn more about how we fact check our content for accuracy. Checklist of the Non-native Plants of Southern Nevada. University of Nevada, Reno, College of Agriculture, Biotechnology & Natural Resources Extension. Integrated Crop Management- Common Sunflower- Helianthus annuus L. Iowa State University Extension and Outreach How Sunflowers Move to Follow the Sun. University of California, Berkeley- Rausser College of Natural Resources. Allelopathy. University of Florida Institute of Food and Agricultural Sciences- Gardening Solutions.