Zinnias – Part One
Have you included zinnias in your garden this year? If so, you’re in good company, since the National Garden Bureau has designated 2000 the “Year of the Zinnia.” These easy, long-blooming tender annuals provide lots of color for the summer garden. The plants come in a variety of sizes, from 6-inch dwarfs to almost 4 feet high, and the flowers range from tiny button-like heads to large heads with double petals, in almost every color except true blue.
Zinnias are American natives that originated from the Southwest U.S., Mexico and Central America. The zinnia was named after the 18th century German botanist Dr. Johann Gottfried Zinn, who wrote the first description of this nondescript wildflower that grew in the Mexican deserts in the 18th century. Original wild zinnias were small, weedy, dull purplish-red, daisy-like flowers with single petals and a protruding cone in the middle. It would take nearly a century before European breeders seriously began developing it as a garden plant. Early varieties were introduced in the U.S. in 1796, with double forms appearing in the mid 1800’s, but the plant didn’t really take off until 1920, when Bodger Seeds Ltd. introduced the dahlia-flowered “Giant Dahlia,” and “California Giant,” a natural mutation of “Mammoth.” The large, flat-flowered heads and multiple colors started a new trend in plant habit
Hybridizers have turned this lowly wildflower into one of the most popular bedding plants. Zinnias now come in a wide variety of flower forms: single, semidouble, or double. Single-flowered zinnias have just one row of petals and the center of the flower is exposed. Double-flowered zinnias, with so many rows of petals that the center is hidden, have several shapes. Beehive types have small blooms with stacks of flat petals that resemble little beehives. Button-type flowers are similar to beehive except it’s flatter. The edges of each petal on cactus-shaped flowers roll under and the petal twists and bends. The petals on dahlia-flowered zinnias are large and flat and usually semi-double, which means that the flowers have many rows of petals but the center can be seen.
Although there are more than a dozen species of zinnias, only a few species, all annuals in our climate, are regularly planted in gardens:
Zinnia elegans is the most common zinnia, and comes in heights up to 3 feet with single or double flower heads from 1 to 7 inches across. They bloom in all colors: pink, rose, red, cherry, lavender, purple, orange, salmon, gold, yellow, white, cream and light green. Some flowers are solid colored, while others are multicolored or zoned. Flower shape varies from round, domed or ball-shaped to dahlia- or chrysanthemum-like flowers. Tetraploid varieties (they have four, rather than the normal two, sets of chromosomes) were developed in the 1950’s that produced larger flowers on stronger stems, and displayed vigorous growth and increased disease resistance. Hybrid varieties were soon developed after that. Some common varieties of Z. elegans include:
The ” Border Beauty” series has 3½ inch, dahlia-like flowers that are semidouble to fully double, on 20-inch plants.
The “Peter Pan” series are dwarf hybrids. Very large, slightly curled double flowers, up to 5 inches wide, are borne on compact 12-inch plants. Seven separate colors in this series have been recognized as All-American Selections (AAS) winners.