How Tall Will A Sunflower Grow Before It Grows Its First Flower

Sunflowers thrive in hot weather with little care.

Helianthus sunflower is native to North America and can be found growing wild throughout as an annual that reseeds itself. Sunflower varieties are available in a wide range of flower colors, blossom size and plant height. Easy to grow in full sun locations with well-draining soil, sunflowers are becoming an alternative crop for agriculture. Sunflower varieties fall into three groups based on the plant’s height, with a fourth category that encompasses the relatively new pollenless sunflower. Flower buds do not develop on a sunflower until the plant has reached its full height. Does this Spark an idea?


Giant sunflowers are often what people first think of because the plant’s large, bright flower head can grow to diameters of 6 to 14 inches. The flower head of giant sunflowers develops an abundance of seeds, which can be harvested for edible snacks or left on the plant for wild bird feed. The giant sunflower grows from 10 to 15 feet tall, depending on the variety and growing conditions. Giant sunflowers will reach close to these heights before the flower bud develops. Favorite giant sunflower varieties include “American Giant,” “Cyclops,” “Giganteus,” “Kong,” “Mammoth Russian” and “Paul Bunyan.”


Semidwarf cultivars of sunflowers are more suited for home landscapes and gardens, reaching heights of 3 to 8 feet with flowers that are 5 to 10 inches in diameter. Unlike giant sunflowers that may need staking or support because of their height and large flowers, semidwarf sunflowers can be grown without staking, but still give the garden the impression of the larger variety. There is an ever-growing selection of semidwarf sunflowers with blooms in a variety of colors; “Italian White” and “Jade” have white blooms, while “Ring of Fire” and “Soraya” are orange flowering and “Cappuccino” and “Chianti” have burgundy blooms.


For the gardener who desires sunflowers but is restricted by space, dwarf sunflower cultivars offer the addition of these bright flowers without the size. Dwarf sunflowers grow less than 3 feet in height, making the plant ideal for gardens, borders and containers. The plant generally will be bushier with multiple side stems growing. Some, like “Sunset,” have a large, 10-inch flower, while other dwarf varieties, such as “Elf,” “Sundance Kid” and “Teddy Bear,” bloom with 4- to 5-inch flowers.


A relatively new variety of sunflowers was introduced in 1988 that does not produce the bright yellow pollen associated with other cultivars. Pollenless sunflowers are ideal for the home gardener who wishes to use sunflowers in fresh cut floral arrangements or as dried flowers. Depending on the variety of pollenless sunflower you grow, the plant can reach a height of 2 to 8 feet, though most are in the 4- to 5-foot range. The sunflowers generally are smaller, 3 to 4 inches, like “Moonshadow,” “Munchkin,” “Peach Passion,” “Starburst Lemon Arora” and “Shamrock Shake,” while “Ruby Moon,” “Joker” and “Full Sun” varieties will produce larger, 5- to 10-inch-diameter flowers.