They come in sizes great and small, from foot-wide sunflowers to tiny baby's breath, and they can be found in nearly every color of the rainbow. They're flowers and they've inspired gardeners for centuries with their breathtaking beauty and great variety. Given their varied nature, one can't help but wonder what affects the size of flower blooms.
A Bloom's Size Is a Product of its Function
The average size of a plant's flower bloom is often a product of its function and to understand that, one needs to consider why plants flower in the first place. Flowers exist for one purpose only -- pollination. The size, color and scent of a flower attract beneficial insects which carry pollen from one plant to another, causing fertilization and, ultimately, seeds. Thus, the larger the flower, the greater the amount of pollen and seeds it can potentially create.
Flower Blooms Differ in Size and Number
But not all flowering plants can support huge blooms. For instance, the sturdy sunflower's growth is often measured in feet, with the world record holder clocking in at over 25 feet. Such great heights can only be achieved with stronger but fewer stems. Fewer stems mean fewer flowers, thus sunflower blooms are large in size to make up for their smaller number of flowers. Tiny baby's breath, on the other hand, may have delicate stems, but what it lacks in brawn, it makes up for with large masses of flowering blooms.
Environmental Factors Matter Too
While the potential size of any flowering bloom is coded in the plant's DNA, environmental factors matter too. When conditions are right -- ample sunshine, the right amount of water, a lack of competition from surrounding plants -- plants can produce flower blooms that are large compared to their genetic standards. On the other hand, poor conditions -- a late frost, lack of sunshine, too much or too little water -- can stress a plant to the point that the size of its blooms is compromised.
The Largest Flowering Bloom
The plant capable of producing the largest flower bloom in the world is the rafflesia arnoldii. A parasitic plant by nature, it can produce a bloom up to 3 feet in diameter which can weigh as much as 15 pounds. This odd plant is rarely cultivated by avid gardeners, however, as its single large bloom gives off a scent comparable to rotting meat, resulting in its well-earned nickname, the corpse flower.
Some Plants Bloom in a Variety of Sizes
One of the most varied flowering plants in terms of bloom size is the dahlia. When selecting dahlia bulbs, gardeners can pick from six bloom sizes ranging from large 10-inch giants to 2-inch mignons as well as 11 different bloom categories including cactus, single and peony type, to name a few.