As the season warms, the pansy fades. What to do? Welcome the zinnia to your garden party! The colorful and hardy zinnia is no shrinking violet. It’s the belle of the ball. A summer flower garden requires plants with three basic elements: ease of propagation, heat and drought tolerance, and dazzling color. The zinnia fits the bill.
Zinnias love heat. Planting when the nighttime temperatures are still below 60 degrees does not please the zinnia. It’s best to postpone sowing seeds until the soil has consistently warmed. In Central Virginia, zinnia seeds can be planted in late May, late June, and even late July.
The zinnia is one of the easiest and most satisfying flowers to grow. It’s considered an annual, meaning that it goes from seed to flower to seed quickly or in one growing season. Annuals grow from seed or reseed themselves every year. Unlike perennials, the zinnia doesn’t need several seasons to establish itself. The seedlings can pop up within days and zinnia flowers bloom quickly and keep blooming until frost. Beware, however, zinnias require well-drained soil and lots of sun. Don’t select boggy or shady sites.
Brilliant colors, varieties
Except for blue, zinnias come in nearly every bright and pastel hue. Cultivar names include, Candy Cane, Persian Carpet and Pop Art. There are varieties called daisies, dahlias spiders and quill-leaf cactus. The flowers can be “singles,” with petals lined up in a row around an open center, semi-doubles, or doubles.
Zinnia elegans, reaching the height of 12 to 14 inches, remains the classic selection for rear borders. Shorter versions called Thumbelina grow a mere six to eight inches tall. There is even a creeping variety, a Mexican native, called Zinnia angustifolia which does well as a ground cover or in containers.
Powdery Mildew: Arch enemy of zinnias
Zinnias are native to Mexico and southern North America. So they prefer hot and dry weather. A word of caution: a wet summer can prove difficult for the zinnia. Too much moisture causes powdery mildew and leaf spot.
All zinnias are susceptible to mildew. If and when mildew occurs, try to strip foliage and destroy it to eliminate spores that can further spread mildew.
Consider planting mildew resistant varieties. Introduced in 2009, Zahara zinnias top out between eight and 12 inches. Zahara is one of the first varieties to be truly disease resistant.
Like Zaharas, the Profusion Series (hybrids between Z. elegans and Z. angustifolia) are resistant to mildew.
Most of the time, zinnias are low maintenance. They don’t require much in the way of fertilizing, and they don’t need mulching. Since they’re fast-growing, they shade out weeds. Although not a native plant, zinnias attract butterflies, pollinators and hummingbirds.
Zinnias as cut flowers
Their long strong stems make them the perfect selection for bouquets and floral arrangements. Tall varieties best for cutting include State Fair and Benary’s Giant. Cut the stem at an angle just above a bud joint. Remove most of the leaves before placing them in water.
Deadheading will encourage more flowers on your zinnias. Deadheading is the practice of cutting off flowers after they’ve reached their peak. Regular deadheading stimulates the zinnia to produce more flowers rather than seeds.
Virginia McCown is a master gardener living in Central Virginia along with her garden and assorted creatures both great and small.