The year of the zinnia

KENNEWICK -- It's the "Year of the Rabbit" for the Chinese, but it's also the "Year of the Zinnia" for U.S. gardeners.

Each year the National Garden Bureau, representing the professional horticulture industry, selects one flower to be showcased.

Plants selected for this honor are chosen because they are popular, easy to grow for gardeners, widely adaptable and versatile.

The zinnia, this year's honoree, is an old garden favorite. The ancestor of the modern zinnia is Zinnia elegans, native to Mexico.

As a native species, Zinnia elegans didn't look attractive to the Spanish colonials who "discovered" this small plant with purple-red daisylike flowers. Ugly or not, zinnias were taken to Europe where they received their scientific name in the 1700s from Dr. Johann Gottfried Zinn, the first botanist to write about them.

Probably because native zinnias were not particularly attractive plants, breeders didn't pay much attention to them for about 100 years. The result of their initial efforts was a double-flowered plant that was still not pretty enough to create excitement in the gardening world. In 1920, additional efforts by breeders yielded two fairly attractive varieties with dahlia-like flowers, 'Giant Dahlia' and 'California Giant.'

Over the years, continued breeding efforts have yielded common zinnias in different sizes, from 8 inches to over 3 feet in height, and in a variety of bright ly colored flower forms. Zinnia flower colors include yellow, gold, pink, rose, red, orange, salmon, purple, ivory and white. The cheery flowers of the common zinnia (Zinnia elegans) will keep coming through the summer only if their faded flowers are removed regularly. This practice is called deadheading.

While the common zinnia proved a dependable garden flower in our grandmothers' gardens, today's gardeners often find the required deadheading and tendency to develop mildew too much trouble. For more modern zinnias, plant breeders have looked to another native Mexican zinnia, Zinnia angustifolia, for help. Breeding efforts have combined the best traits of these two species and have yielded more compact zinnias that don't require deadheading to keep them flowering. These new hybrids are also resistant to powdery mildew and are more tolerant of heat and humidity.

My current zinnia favorites are in the Profusion series of zinnias. Introduced in 1994, 'Profusion Orange' was the first in the series with orange flowers. White, cherry, apricot, gold, and scarlet-orange flowered members of the series followed. Profusion zinnias have 2-inch single and double flowers. Their compact branched plants grow to 12 to 18 inches tall and 24 inches wide. They keep flowering through fall and don't require deadheading.

I hope to try some of the Zahara series of zinnias this year. Zahara zinnias are also hybrids of the Z. elegans and Z. angustifolia. This newest series touts flowers that are 20 per cent larger than the Profusion series. Zahara flower colors include coral rose, orange-red, scarlet, white, yellow, double cherry, double orange-red and a delightful white and pink bi-color called Starlight Rose.

Zahara zinnias are heat-loving plants that thrive under hot, sunny conditions. Once established, they're drought tolerant. Their bushy plants produce flowers all season long and grow to a height and width of 12 to 18 inches with double-flowered varieties growing 16 to 20 inches in size.

Both the Zahara and Profusion zinnias are great in containers and flower beds.

The WSU Extension Master Gardeners will be planting some of the Zahara zinnias in the Formal Garden in The Master Gardener Demonstration Garden this year. Drop by during the summer to see these tough but pretty new zinnias.

* Marianne C. Ophardt is a horticulturist for the Washington State University Benton County Extension.