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HELIANTHUS annuus 'Florenza'

Image of Helianthus annuus 'Florenza'

Ernst Benary® Inc.



Botanical Name

HELIANTHUS annuus 'Florenza'

Plant Common Name

Annual Sunflower

General Description

This 2002 Ernst Benary introduction is a Fleuroselect Gold Medal Winner admired for its beautiful bicolored sunflowers. The robust plant is strong-stemmed and produces lots of medium-sized, sunflowers with black centers and bicolored petals that are pale yellow at the tips and reddish brown at the base. Like most cultivated sunflowers, 'Florenza' is day-neutral, which means it will bloom at any time of the year regardless of day/night length. Its are ideal for cutting and have an estimated vase life of eight to ten days.

The sunflower is one of the best known garden flowers. Its big bold daisies track the sun, hence the common name. This warm season annual is uncommonly easy to grow and economically important for the production of sunflower seeds, cooking oil and cutflowers. It is a New World native that exists throughout the whole of North America down to Central America. Natural populations can vary widely in height but most are tall, upright with multiple side branches that extend from a sturdy central stem.

Sunflower leaves are very distinctive. They are large, medium green and heart-shaped with a rough, slightly hairy surface. Flowering typically occurs when temperatures are warm and nights short. Mature plants produce huge daisies that come in an array of sizes and harvest colors. The fresh flowers draw lots of insect pollinators, including bees and butterflies. It is important to allow the mature flowerheads to dry because the seeds within feed wild birds and mammals.

Grow sunflowers in full sun and average soil with good drainage. It is best to directly sow the seeds in the ground in the late spring. Tall plants with few side branches may require staking—sunflowers often fall when subjected to high winds and heavy rain. After flowering and setting seed, these short-lived annuals will die. If you desire continuous summer sunflowers, plant seeds every two weeks in succession from mid-spring to early summer. These outstanding annuals make superb additions to cutting garden or vegetable plots. Children also love them because they are fun to plant and grow. Sunflower heads can also be cut with their seeds intact, dried indoors and brought outside to feed wildlife in winter.

Sunflowers emit a substance from their roots and germinating seeds that inhibits the germination of other seeds around them.


  • AHS Heat Zone

    12 - 1

  • Sunset Zone

    A1, A2, A3, H1, H2, 1a, 1b, 2a, 2b, 3a, 3b, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24

  • Plant Type


  • Sun Exposure

    Full Sun

  • Height

    3'-4' / 0.9m - 1.2m

  • Width

    1'-2' / 0.3m - 0.6m

  • Bloom Time

    Late Spring, Early Summer, Summer, Late Summer, Early Fall, Fall, Indeterminate

  • Native To

    North America, Mexico, Central America

Growing Conditions

  • Soil pH

    Neutral, Alkaline

  • Soil Drainage

    Well Drained

  • Soil type

    Clay, Loam, Sand

  • Growth Rate

    Very Fast

  • Water Requirements

    Drought Tolerant, Average Water

  • Habit


  • Seasonal Interest

    Summer, Fall

Ornamental Features

  • Flower Interest


  • Flower Color

    Light Yellow, Dark Red, Brown

  • Flower Color Modifier


  • Fruit Color

    Chocolate, Ivory, Black

  • Fruit Color Modifier


  • Foliage Color (Spring)


  • Foliage Color (Summer)


  • Foliage Color (Fall)


  • Fragrant Flowers


  • Fragrant Fruit


  • Fragrant Foliage


  • Bark or Stem Fragrant


  • Flower Petal Number


  • Repeat Bloomer


  • Showy Fruit


  • Edible Fruit


  • Showy Foliage


  • Foliage Texture


  • Foliage Sheen


  • Evergreen


  • Showy Bark


Special Characteristics

  • Usage

    Container, Cutflower, Edible, Herb / Vegetable, Mixed Border, Wildflower

  • Sharp or Has Thorns


  • Invasive


  • Attracts

    Birds, Butterflies

  • Self-Sowing