Zinnias

Once considered a Mexican weed, the zinnia began to gain popularity as a garden annual in the mid to late 1800s, thanks to hybridization. Those early, not-so-attractive single blooms evolved into doubles, and with the introduction of the giant dahlia-like hybrids in 1920, zinnia popularity soared, according to the National Garden Bureau, which is celebrating 2000 as the "Year of the Zinnia."

Today, we've come full circle in our appreciation of the annual that brings us blooms late spring to frost. As hybridizers tinkered, zinnia flowers not only grew in size and petal count, but the color range increased and now lacks only a blue. Plant heights climbed to 3 or 4 feet and came down again as dwarf varieties were introduced.

With such variations in height, form and color, zinnias can be used for edging and borders or colorful backdrops, massed in mixed beds, or to perk up vegetable gardens or containers. The taller types are a must in the cutting garden. Compact, low-growing, single flowering zinnias are favorite summer bedding plants.

An assortment of zinnia varieties is usually available in local garden centers in the spring, ready to plant in a sunny area in a well-draining, compost enriched soil. The annuals need warm weather to thrive. And they are at their best with good air circulation, especially varieties with broader leaves. Seed is available locally and through mail-order catalogs.

The ever-popular common or garden zinnia, aka old-maids, (Zinnia elegans), was grown in Grandmother's garden and lingers in landscapes today, providing an ongoing supply of bright, cheery color. This species has spawned numerous strains 6 inches to 3 feet in height carrying flowers 1 to 6 inches across and available in various forms. `Dreamland' produces 3- to 4-inch, dahlia-like blooms in apricot, coral, red, scarlet, pink, rose, yellow and ivory on 12inch plants, giving a gardener the idea of planting an entire sun garden in vivid color.

White flowers bring out the best in the colors of surrounding blooms, and one outstanding white flower for our mid, hot summers is the white Zinnia angustifolia, or Z. linearis.

Z. angustifolia `Crystal White,' a pure white zinnia with narrow green foliage, is a 1997 All America Selections winner that produces nonstop blooms on a mounding 10-inch plant. There's no need to deadhead spent blooms. Sun and a well-draining, organically enriched soil will help ensure months of flowers. Water during long, dry stretches of summer. An occasional application of fertilizer will boost performance.

`Crystal White' closely resembles other narrow-leafed zinnias that adapt easily to our climate. Frequently called Mexican zinnias, these are resistant to mildew and other fungal diseases that can pester varieties of Z. elegans.

Look for Z. angustifolia in orange, too. Plant with Salvia farinacea or purple gomphrena for vivid summer/fall color. Plants of both the white and orange varieties are usually available in spring in Houston nurseries.

All Z. elegans make good cut flowers and usually last about a week in a vase. Z. angustifolia is a perfect substitute for baby's breath as it adds airiness to an arrangement.

Cut the flowers in the morning before the sun is too hot. Select those that aren't fully open or buds that have begun to open, but avoid tightly closed buds as they will not open once cut. Immediately place cut stems in a bucket of water so they won't clog with air bubbles. Indoors, recut the stems under water and remove any foliage that would be under water once the flowers are arranged in a vase. Let the flowers "rest" for a few hours before creating your arrangement.

Also often available locally are two 1999 AAS Gold Medal winners, `Profusion Orange' and `Profusion Cherry.' Tolerant of foliar diseases, `Profusion' zinnias freely produce 2- to 3-inch single blooms on mounded plants 12 to 18 inches tall and have a spread slightly broader than their height. The mounding habit resembles that of impatiens, showing color from all sides. No dead-heading is required, but gardeners may prefer to remove faded blooms. Best results come with full sun and good drainage in the garden. Mass them by the dozen - or in containers.

Less common is Z. haageana, a bi-colored zinnia with 2-inch blooms. `Persian Carpet' is a compact plant about 16 inches tall. Seed is available from Park Seed.

Zinnias love sun, good air circulation and good drainage. The National Garden Bureau recommends fertilizing zinnias in the garden at least twice during the growing season with a balanced granular or water-soluble fertilizer. Or use a slow-release fertilizer when planting. Container plants can be fed monthly with a soluble fertilizer diluted according to label instructions, or a time release fertilizer can be worked into the potting mix when planting.

While narrow-leaf zinnias are more disease-resistant, there are two problems that can pester varieties with broader leaves - powdery mildew, which covers the foliage with a light gray mold, and alternaria blight, the fungus that causes reddish-brown spots on foliage and flowers. Some gardeners camouflage the foliage of older, more disease-prone varieties by planting shorter flowers in front. But a little prevention can help: Avoid wetting the foliage and space the plants to provide good air circulation.