20 Tall Flowers That Make a Strong Impact

By
Marie Iannotti
Garden Writer Marie Iannotti
Marie Iannotti
Marie Iannotti is a life-long gardener and a veteran Master Gardener with nearly three decades of experience. She's also an author of three gardening books, a plant photographer, public speaker, and a former Cornell Cooperative Extension Horticulture Educator. Marie's garden writing has been featured in newspapers and magazines nationwide and she has been interviewed for Martha Stewart Radio, National Public Radio, and numerous articles.
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Updated on 06/17/21
tall verbena

The Spruce / Kara Riley

There are several annual and perennial flowers that are tall enough for the back of a garden bed and bold enough to make their own statement. Tall flowers help to add structure and depth to a garden bed. They also can be used as a living privacy fence or to hide an unattractive backdrop. Plus, because they're so large you'll be able to see them from afar, as opposed to small flowering plants that you can only appreciate up close.

Here are 20 tall flowers that will make a strong statement in your garden.

  • 01 of 20

    Floss Flower (Ageratum houstonianum)

    Ageratum houstonianum flowers

    The Spruce / Marie Iannotti

    Floss flowers can reach around 2.5 feet high with a 6- to 18-inch spread. They produce clusters of fluffy blooms from June all the way until frost. These plants are easy to grow as long as they have even soil moisture with good drainage. Deadheading (removing the spent blooms) is not necessary for continued blooming, but it will make for a tidier appearance. Frost will quickly kill the plants in the fall. In addition, extremely hot summer weather might limit blooming.

    • USDA Growing Zones: 2 to 11 (annual)
    • Color Variations: Blue-purple, pink, red, white, bicolors
    • Sun Exposure: Full sun to part shade
    • Soil Needs: Average, moist, well-drained
  • 02 of 20

    Amaranth (Amaranthus spp.)

    Amaranth plant with fuchsia-colored flower panicles clustered on branches with waxy veined leaves

    The Spruce / K. Dave

    Several species within the Amaranthus genus are commonly known as amaranth or love lies bleeding. An excellent tall flower species is A. caudatus, which can grow to 3 to 5 feet with long panicles of dangling blooms. Another tall species is A. hypochondriacus, which grows to around 4 feet with flowers held in upright panicles in shades of red, purple, gold, and green. All the amaranths are easy to grow from seed. However, they are susceptible to many common garden pests.

    • USDA Growing Zones: 2 to 11 (annual)
    • Color Variations: Red, pink, purple, yellow, orange, green
    • Sun Exposure: Full sun to part shade
    • Soil Needs: Average, moist, well-drained
  • 03 of 20

    Castor Bean (Ricinus communis)

    Castor bean plant with spiky red seed capsules on flower stalk closeup

    The Spruce / Evgeniya Vlasova

    Castor bean plants are tall flowers that can reach around 6 to 10 feet high with a 2- to 4-foot spread. They grow quickly with glossy green foliage. In the summer and fall they bloom with somewhat insignificant flower spikes. It’s the reddish-brown seed capsules that have the real ornamental value. While this plant provides lots of visual interest to the garden, all parts of it are toxic when ingested to people and animals. So be sure to plant it away from areas with children and pets. Also, situate it somewhere that's protected from strong winds.

    • USDA Growing Zones: 9 to 11
    • Color Variations: Green-yellow, red
    • Sun Exposure: Full sun
    • Soil Needs: Rich, moist, well-drained
  • 04 of 20

    Spider Flower (Cleome hassleriana)

    spider flower plant

    The Spruce / Marie Iannotti

    Spider flowers start blooming early and get better as the season rolls along. The first blooms begin when the plants are only about 1 foot tall. As the plants grow, more flowers form at the top. Although height depends on the variety you are growing, most can reach 4 to 5 feet, branching along the way and producing even more flowers. You can direct sow seeds, and the plants easily self-seed in the garden. However, that means if you don't want them to spread you'll have to keep pulling seedlings as they pop up.

    • USDA Growing Zones: 10 to 11
    • Color Variations: White, pink, lavender
    • Sun Exposure: Full sun to part shade
    • Soil Needs: Slightly acidic, medium moisture, well-drained
    Continue to 5 of 20 below.
  • 05 of 20

    Cosmos (Cosmos sulphureus, Cosmos bipinnatus)

    Cosmos plant with daisy-like flowers with pink and white petals surrounding yellow center closeup

    The Spruce / Leticia Almeida

    Cosmos is one of the most undemanding tall flowers you can grow. There are two common species of cosmos. C. bipinnatus has feathery foliage and daisy-like flowers with yellow centers, and some varieties reach up to 4 feet tall. C. sulphureus is a taller plant, growing to around 6 feet with yellow or orange flowers. Cosmos will repeat flower from summer to fall even without deadheading. However, the plants will last longer if you either deadhead or wait until flowering declines and shear back the whole plant by about half.

    • USDA Growing Zones: 2 to 11 (annual)
    • Color Variations: White, pink, red, yellow, orange
    • Sun Exposure: Full sun
    • Soil Needs: Medium moisture, well-drained
  • 06 of 20

    Kiss-Me-Over-the-Garden Gate (Persicaria orientale)

    Kiss-me-over-the-garden gate plant with small purple-pink flower clusters on thin stems

    The Spruce / Evgeniya Vlasova

    Persicaria orientale, commonly known as kiss-me-over-the-garden gate or knotweed, is a quick-growing annual with spikes of purple-pink flowers that bloom from summer to fall above the foliage. The plant reaches around 4 to 7 feet high with a 2- to 4-foot spread. It will attract hummingbirds and other pollinators to your garden. But strong winds can damage it, so it must be in a protected site. Mulching is recommended to retain soil moisture.

    • USDA Growing Zones: 2 to 11 (annual)
    • Color Variations: Purple-pink
    • Sun Exposure: Full sun to part shade
    • Soil Needs: Medium moisture, well-drained
  • 07 of 20

    Flowering Tobacco (Nicotiana sylvestris)

    Flowering tobacco plant with small pink trumpet-shaped flowers on thin stems closeup

    The Spruce / Autumn Wood

    Flowering tobacco is a stately tall flower with its clusters of trumpet-shaped blooms. It can grow to around 5 feet and produces a jasmine-like scent in the evenings. During the day, the flowers partially close, and no scent it released. Because of this habit, these are great plants for a patio or deck where you spend time in the evening. However, they should not be grown near tomatoes or other members of the nightshade family, as they all are susceptible to some of the same plant viruses.

    • USDA Growing Zones: 10 to 11
    • Color Variations: White, yellow-green, pink, red
    • Sun Exposure: Full sun to part shade
    • Soil Needs: Rich, moist, well-drained
  • 08 of 20

    Sunflower (Helianthus annuus)

    Sunflower with radiating yellow petals and large yellow centers closeup

    The Spruce / Ana Cadena

    Annual sunflowers bloom in the summertime with their broad flowers on upright stalks. Gardeners have several options when it comes to these annuals. The traditional yellow sunflowers are still popular, but now you can also find cultivars in rich burgundy, deep mahogany, and many bicolors. They grow between roughly 3 and 10 feet high. And they don't require much care, though you can remove depreciated foliage for a tidier appearance. Birds love to feed on the seed heads. However, note that this plant self-seeds so readily that it is considered a noxious weed in some areas.

    • USDA Growing Zones: 2 to 11 (annual)
    • Color Variations: Yellow, red, brown
    • Sun Exposure: Full sun
    • Soil Needs: Average, moist, well-drained
    Continue to 9 of 20 below.
  • 09 of 20

    Mexican Sunflower (Tithonia rotundifolia)

    Mexican Sunflower (Tithonia)

    The Spruce / Marie Iannotti

    Mexican sunflowers are easy to grow and virtually pest-free. The species typically grows to around 4 to 6 feet tall, though dwarf cultivars are also available. These tall flowers love hot days and do equally well in high humidity or drought conditions. However, they can take a while to start blooming. To speed things along, start seeds indoors six to eight weeks before your area's last projected frost date in the spring.

    • USDA Growing Zones: 2 to 11 (annual)
    • Color Variations: Orange-red with yellow center
    • Sun Exposure: Full sun
    • Soil Needs: Average, dry to medium moisture, well-drained
  • 10 of 20

    Tall Verbena (Verbena bonariensis)

    tall verbena with purple flowers

    The Spruce / Kara Riley

    Tall verbena, sometimes known as Brazilian vervain, is an unusual plant that forms a low clump of leaves and then sends up tall, bobbing stems with clusters of flowers. It can grow to around 4 feet tall and blooms from summer to fall. The plant is excellent at attracting butterflies to the garden, and it can tolerate many soil types as long as there is good drainage. The plant tends to self-seed throughout the garden, so you must be on top of removing seedlings if you want to limit its spread.

    • USDA Growing Zones: 7 to 11
    • Color Variations: Pink-purple, lavender
    • Sun Exposure: Full sun to part shade
    • Soil Needs: Average, moist, well-drained
  • 11 of 20

    Hardy Hibiscus (Hibiscus moscheutos)

    Hardy hibiscus plant with large light pink flowers in shrub on side of brick wall

    The Spruce / Leticia Almeida

    Hardy hibiscus, also known as swamp mallow, is a shrub-like perennial that’s native to wet soils, such as river banks. In the summertime, it blooms with showy flowers that have five overlapping petals. And it grows to around 3 to 7 feet high with a 2- to 4-foot spread. This plant tolerates heat and humidity quite well and can be used in a rain garden. It’s important never to let its soil dry out and to protect it from strong winds.

    • USDA Growing Zones: 5 to 9
    • Color Variations: White, pink
    • Sun Exposure: Full sun
    • Soil Needs: Rich, moist
  • 12 of 20

    Joe Pye Weed (Eutrochium purpureum)

    Joe Pye weed plant with multi-stemmed clusters of tiny pink and white flower clusters

    The Spruce / Adrienne Legault

    The tall flowers of Joe Pye weed arrive in the summertime and persist through early fall. The tiny blooms come in attractive clusters and have a pleasant vanilla scent. They’re known for attracting butterflies to the garden. This plant can reach around 5 to 7 feet tall and is easy to care for. Just make sure the soil doesn't dry out, or the leaves can scorch. Joe Pye weed looks best if you have the space to group several plants for more ornamental impact.

    • USDA Growing Zones: 4 to 9
    • Color Variations: Pink
    • Sun Exposure: Full sun to part shade
    • Soil Needs: Rich, moist
    Continue to 13 of 20 below.
  • 13 of 20

    Hollyhock Mallow (Malva alcea)

    Hollyhock mallow plant with pink, white and red trumpet-shaped flowers and buds on flower spikes

    The Spruce / Evgeniya Vlasova

    Hollyhock mallow grows to around 2 to 4 feet tall with a spread of less than 2 feet. It features five-petal flowers that stretch around 2 inches across and bloom in the summer to early fall. Butterflies love the flowers. To promote more blooming, remove the spent flower spikes. While it brings lots of ornamental value, this perennial does tend to be short-lived. But it can self-seed fairly well to produce new plants.

    • USDA Growing Zones: 4 to 7
    • Color Variations: Pink
    • Sun Exposure: Full sun to part shade
    • Soil Needs: Medium moisture, well-drained
  • 14 of 20

    Delphinium (Delphinium spp.)

    Delphinium plant with bright blue columnar spikes clustered with small blue flowers in garden

    The Spruce / Autumn Wood

    Delphinium, also known as larkspur, is a large genus of flowering plants that come in varying sizes. The Pacific Hybrid group includes tall flowers that grow to around 4 to 8 feet high. The flowers bloom in the summer clustered together on columnar flower spikes. While these plants offer lots of visual interest in the garden, they are fairly high-maintenance. They usually need staking to keep them upright, along with deadheading and pruning of spent growth. 

    • USDA Growing Zones: 3 to 7
    • Color Variations: Blue, violet, pink, white
    • Sun Exposure: Full sun
    • Soil Needs: Rich, medium moisture, well-drained
  • 15 of 20

    Canna (Canna spp.)

    Canna plant with showy bright orange flowers on dark red stem

    The Spruce / Adrienne Legault

    The Canna genus includes tropical and subtropical plants with showy flowers. On average, they grow between 1.5 and 8 feet tall, though exact height depends on the variety. The flower spikes rise above the foliage during the summer. These plants add rich, warm colors to the garden. But they have poor cold tolerance and must be brought indoors if the temperature nears 40 degrees Fahrenheit. 

    • USDA Growing Zones: 7 to 10
    • Color Variations: Red, orange, yellow, pink, white, bicolors
    • Sun Exposure: Full sun
    • Soil Needs: Rich, moist, well-drained
  • 16 of 20

    Elecampane (Inula helenium)

    Elecampane plant with yellow sunflower-like flowers with thin petals closeup

    The Spruce / Evgeniya Vlasova

    Elecampane is a flowering perennial that’s part of the aster family. Its blooms have a sunflower-like appearance but with very thin petals. The flowers stretch around 2 to 3 inches across and appear from mid-summer to early fall. The plant overall can reach around 3 to 6 feet high. It’s tolerant of a variety of soil conditions. But it might need staking if it gets too tall.

    • USDA Growing Zones: 3 to 7
    • Color Variations: Yellow
    • Sun Exposure: Full sun to part shade
    • Soil Needs: Moist, well-drained
    Continue to 17 of 20 below.
  • 17 of 20

    Red Hot Poker (Kniphofia uvaria)

    Red hot poker plant with small orange and yellow tubular flowers on spikes

    The Spruce / Evgeniya Vlasova

    Red hot poker, also known as torch lily, provides unique visual interest to the garden. Its small, tubular flowers arise on spikes above the blue-green basal foliage in the late spring to early summer. They start out red but mature to yellow. The plant itself grows to around 3 to 4 feet high with a slightly smaller spread. Red hot poker is fairly easy to maintain. But it’s important to watch out for poor drainage, as soggy soil can kill it.

    • USDA Growing Zones: 5 to 9
    • Color Variations: Red/yellow
    • Sun Exposure: Full sun
    • Soil Needs: Average, medium moisture, well-drained
  • 18 of 20

    Monkshood (Aconitum napellus)

    Monkshood plant with long thin stems and dark green leaves with clusters of white and purple hooded blooms

    The Spruce / Autumn Wood

    Monkshood has an upright growth habit, reaching around 2 to 4 feet tall with a 1- to 1.5-foot spread. Clusters of small, hooded blooms arise in the summer above the dark green foliage. This plant needs moist but not soggy soil, and its soil also never should dry out. It doesn’t have any serious issues with pests or diseases. However, all parts of the plant are toxic via ingestion and skin contact, so take care when working with it.

    • USDA Growing Zones: 3 to 7
    • Color Variations: Blue-purple
    • Sun Exposure: Full sun to part shade
    • Soil Needs: Rich, moist, well-drained
  • 19 of 20

    Foxglove (Digitalis purpurea)

    Foxglove plant with tall flower spikes with buds on top and purple-pink long, tubular blooms in garden

    The Spruce / Evgeniya Vlasova

    Foxglove generally reaches around 2 to 4 feet tall, though it occasionally can hit 5 feet. The flower spikes arise from a rosette of foliage at the plant’s base in the late spring. Several long, tubular blooms are grouped on the spikes, which attract hummingbirds to the garden. This perennial is short-lived and won’t produce flowers until its second year. It also can look a bit ragged by the late summer. Thus, many gardeners remove their foxglove plants after they’ve flowered and released their seeds for new plants.

    • USDA Growing Zones: 4 to 8
    • Color Variations: Pink, purple, white
    • Sun Exposure: Full sun to part shade
    • Soil Needs: Average, medium moisture, well-drained
  • 20 of 20

    Sneezeweed (Helenium autumnale)

    Sneezeweed plant with yellow daisy-like flowers growing in clumps closeup

    The Spruce / Adrienne Legault

    Sneezeweed is a clump-forming plant that grows to around 3 to 5 feet high with a spread of 2 to 3 feet. In the late summer, it blooms with daisy-like flowers that stretch roughly 2 inches across. They can persist until frost in the fall, bringing interest to the garden at a time when many other plants have finished blooming for the season. This plant does require some pruning maintenance, including deadheading to promote further blooming. Once flowering is done for the season, cut back your sneezeweed by half.

    • USDA Growing Zones: 3 to 8
    • Color Variations: Yellow
    • Sun Exposure: Full sun
    • Soil Needs: Average, medium moisture to wet
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