12 Best Annual Flowers for Full Sun

illustration of full sun annual flowers
Illustration: © The Spruce, 2018

It can get pretty hot sitting in the sun all day. Some plants love it; others faint. Many perennials with deep tap roots and water-conserving leaves can handle lots of sunshine, but annuals that never get the chance to develop an extensive root system tend to struggle. So you have to choose wisely when selecting annual flowers for the sunny spots in your garden. Here are 12 annual flowers that can tolerate full sun.

  • 01 of 12

    Amaranth (Amaranthus)

    Globe amaranth in full sun
    Rikuo Natsuume/Aflo/Getty Images

    There are many species of amaranth. Some are grown strictly as flowers, some for their leaves, and others for use as grain. Two common varieties are love-lies-bleeding (Amaranthus caudatus), with its dangling mauve-pink flowers, and Joseph's coat (Amaranthus tricolor), which features splashy red and yellow leaves.

    Gardeners love these plants for their chenille-like blooms and colorful foliage. They range from a few inches to several feet tall. Plus, they all grow well from seed and can handle various conditions, including living indoors as houseplants or as perennials in the warmer U.S. Department of Agriculture hardiness zones.

    • USDA Growing Zones: 10 to 11
    • Color Varieties: Red, pink, purple, yellow, green, white
    • Sun Exposure: Full sun
    • Soil Needs: Rich, moist, well-draining
  • 02 of 12

    Celosia (Celosia)

    Celosia with red-purple flowers
    Tetsuya Tanooka/Aflo/Getty Images

    If you notice a similarity between the flowers of celosia and amaranth, it's because they are both from the same family. The name celosia comes from the Greek word for "burning" because the flower heads of Celosia argentea look like brilliant flames.

    Another variety is Celosia cristata, also called crested celosia or cockscomb, which has rippled flower heads that look like a rooster's comb. Furthermore, Celosia spicata has subtle flowers that are likened to wheat spikes. Celosia flowers remain attractive for weeks, and most varieties also make great cut and dried flowers.

    • USDA Growing Zones: 9 to 11
    • Color Varieties: Red, pink, purple, orange, yellow, white
    • Sun Exposure: Full sun
    • Soil Needs: Rich, moderate moisture, well-draining
  • 03 of 12

    Spider Flower (Cleome)

    Spider flower (Cleome) with pink blooms
    © Marie Iannotti

    Spider flower gets its common name for the long "legs" that jut out from its blooms. The plant starts flowering from the bottom up, extending its blooming period for weeks. It's a tall flower that branches out and generally can support itself without staking.

    As the flowers fade, slender seed pods form. These plants are prodigious self-seeders, and because most are hybrids you won't know what colors you will get next growing season. Seed can be directly sown anytime after the last frost date.

    • USDA Growing Zones: 10 to 11
    • Color Varieties: White, pink, purple, red, yellow, orange
    • Sun Exposure: Full sun to part sun
    • Soil Needs: Rich, moderate moisture, well-draining
  • 04 of 12

    Cosmos Flower (Cosmos bipinnatus)

    detail shot of a pink cosmos flower
    © Marie iannotti

    Cosmos flowers are about as easy to grow as it gets. You can find them in several rich shades, as well as soft pastels and even white. The flowers are only about an inch across, but they're prolific. The plants are sturdy, growing from around 1 to 4 feet tall, and they intermingle well with other flowers.

    This is another eager self-seeder but not to the point of nuisance. Cosmos are easy to start from seed, as well. Directly sow them anytime after your last frost.

    • USDA Growing Zones: 9 to 11
    • Color Varieties: Pink, purple, red, yellow, orange, white
    • Sun Exposure: Full sun
    • Soil Needs: Average, moderate moisture, well-draining
    Continue to 5 of 12 below.
  • 05 of 12

    Cupflower (Nierembergia)

    Nierembergia plant with lavender flowers
    Eric Van Lokven/Getty Images

    This delicate, charming flower is part of the nightshade family. Nierembergia, which was named for the Spanish Jesuit professor of natural history Juan Eusebio Nieremberg, tends to be used more often than the plant's common name of cupflower. Perhaps that is because there are multiple plants called cupflower.

    Nierembergia is very popular in containers, but it is perfectly at home in the ground and makes a nice edging plant. It has a clumping growth habit and fills out quickly.

    • USDA Growing Zones: 7 to 10
    • Color Varieties: White, purple, blue
    • Sun Exposure: Full sun
    • Soil Needs: Rich, moist, well-draining
  • 06 of 12

    Cypress Vine (Ipomoea quamoclit)

    Cypress vine with pink flowers
    Joshua McCullough/Getty Images

    Tubular, star-shaped flowers and thin, ferny leaves make cypress vine an ornamental climber. The plant is in the same family as morning glory and grows just about as quickly, reaching 10 to 15 feet. It starts setting buds once it grows tall, so be patient.

    You can start it indoors a few weeks before your last frost date or directly seed outdoors after the last frost. As the plant is growing, be sure to give it something to climb or sprawl over, such as a trellis.

    • USDA Growing Zones: 8 to 11
    • Color Varieties: Red, pink, white
    • Sun Exposure: Full sun
    • Soil Needs: Average, medium moisture, well-draining
  • 07 of 12

    Lantana (Lantana camara)

    yellow and pink lantana flowers

    Ji Hyun Park/EyeEm/Getty Images

    If you are lucky enough to live in a climate where lantana is hardy, you might have it growing as a shrub. It also trains easily into a standard or small tree. Many gardeners in colder climates do this and overwinter the plants indoors.

    Lantana flowers are often bicolored or tricolored in wonderful sherbet shades. As with many annual flowers, they bloom throughout the summer. All parts of this plant are poisonous and can cause skin irritation, so handle with care.

    • USDA Growing Zones: 8 to 11
    • Color Varieties: Red, orange, yellow, blue, white
    • Sun Exposure: Full sun
    • Soil Needs: Average, medium moisture, well-draining
  • 08 of 12

    Marigold (Tagetes)

    Marigold 'Queen Sophia' flowers

    Courtesy of National Garden Bureau

    They are so ubiquitous that we sometimes don't give marigolds their due. These flowers are tough little workhorses. They do best in full sun with plenty of air flow and soil that's a little on the dry side. When crowded in damp conditions, they are prone to mildew. Deadheading will get them to bloom repeatedly, though even if you don't bother with it they will bloom again.

    Another underrated feature of marigolds is their use as companion plants. They repel pests, including asparagus beetles, bean beetles, nematodes, and even rabbits.

    • USDA Growing Zones: 9 to 11
    • Color Varieties: Red, orange, yellow, gold
    • Sun Exposure: Full sun
    • Soil Needs: Average, medium moisture, well-draining
    Continue to 9 of 12 below.
  • 09 of 12

    Ornamental Pepper (Capsicum annuum)

    ornamental peppers in reds, yellows, and purples

    Simon Law/Flickr/CC by 2.0

    Ornamental peppers are not necessarily grown for their flowers, but they still offer beautiful color to a garden. The plants grow edible chili peppers that are generally small and difficult to harvest. But people noticed their beauty and thought to put them in flower gardens. Just like the peppers we grow in vegetable gardens, the ornamental types go through several color changes as they ripen. Some have multiple colors on the plant at one time.

    Keep an eye on them while the plants are young and tender, as rabbits like to chew the stems. Once the stems begin to harden off, they are pretty much safe.

    • USDA Growing Zones: 9 to 11
    • Color Varieties: White, yellow
    • Sun Exposure: Full sun
    • Soil Needs: Rich, loamy, slightly acidic, well-draining
  • 10 of 12

    Mexican Sunflower (Tithonia rotundifolia)

    bright orange-red Mexican sunflower
    Maria Mosolova/Getty Images

    The Mexican sunflower is definitely a sun lover. Give it a hot, sunny site, and it will grow and bloom quickly, easily reaching heights of 5 to 8 feet. But it might need some support or staking, especially in windy sites.

    You can directly sow seed after the last frost or start your plants indoors roughly four to six weeks before bringing them outside. But do not rush them. The seedlings can stunt when exposed to cold temperatures.

    • USDA Growing Zones: 8 to 10
    • Color Varieties: Orange-red with an orange-yellow center
    • Sun Exposure: Full sun
    • Soil Needs: Average to poor, low to medium moisture, well-draining
  • 11 of 12

    Verbena Plant (Verbenaceae)

    purple verbena flowers
    Josie Elias/Getty Images

    There are several species of verbena that make great garden plants. Most start blooming early in the season and continue until frost. Options include ground cover verbenas; the tall, airy Verbena bonariensis; and the upright Verbena rigida, which grows to about 3 feet tall.

    Verbena is prone to fungal problems, such as botrytis, if it is grown in damp conditions. Although it needs moist soil to become established, drier conditions will keep a mature plant happy.​

    • USDA Growing Zones: 5 to 11
    • Color Varieties: White, pink, red, blue, purple
    • Sun Exposure: Full sun
    • Soil Needs: Tolerates a variety, well-draining
  • 12 of 12

    Zinnia (Zinnia)

    bright red zinnias
    Michel Gunther/Getty Images

    As true annual flowers for full sun, zinnias love heat and bloom easily. You can even use them for cut flowers, and they will simply bloom again in a day or two. What's more, there is a zinnia color for everyone—from peppermint stripes to eye-popping golds and delicate neutrals.

    Older varieties are prone to powdery mildew in humid weather. This won't stop them from flowering, but it does make the foliage look unattractive. Fortunately, some of the newer series, including 'Profusion' and 'Zahara,' don't have that problem.

    • USDA Growing Zones: N/A
    • Color Varieties: Red, pink, yellow, orange, lilac, purple, green, white
    • Sun Exposure: Full sun
    • Soil Needs: Humusy, well-draining