Zinnias: Annuals with long-lasting color

Many gardeners prefer to plant perennial flowers rather than annual flowers simply due to the fact that healthy perennials that are well-cared for will return year after year, while annuals need to be planted anew each spring. There are some tradeoffs, of course. Even the longest blooming perennials might only bloom for two or three months, with most having a bloom time closer to just a few weeks. By contrast, the majority of annual flowers bloom from spring until frost. We tend to use annuals judiciously, in areas where their long-lasting color can make the most impact.

Take zinnias, for instance. They bloom profusely throughout spring summer and fall, and their wide daisy-like flowers are a favorite of many beneficial insects and pollinators. Thus, we see zinnias frequently used in pollinator gardens and in the borders of vegetable gardens and other edible plantings, where their tendency to attract good insects is highly valued, and their extended bloom ensures these insects will always find the pollen and nectar they crave. As gardeners, we enjoy the additional benefit of their beauty. Zinnias are also popular as cut flowers due to their extended shelf life after being cut.  

Top left: Common zinnia's long-lasting blooms make its a very popular annual. Photo: Audrey, CC BY 2.0

Left, second from top: Zinnia angustifolia, Mexican Zinnias, are much shorter than common Zinnias. Photo: D.J. Stang, CC BY-SA 4.0 Bottom left: Benary's Giants are the most popular zinnias for cut-flower arrangements. Top right:  Profusion zinnias are a cross between Zinnia elegans and Zinnia angustifolia. Bottom right: Thumbelina are dwarf zinnias that top out at six inches high.

Not all zinnias are created equally, of course. There are a number of different species and cultivars within those species that collectively create a wide diversity of flower color and shape. Most frequently used in our landscapes are members of the Zinnia elegans or common Zinnia species, although Zinnia angustifolia (the Mexican Zinnia), Zinnia peruviana (the Peruvian Zinnia), and a few others are also popular.

One of the trendiest cultivar groups is the Profusion series, a group of hybrids from a cross of Zinnia elegans and Zinnia angustifolia. Zinnia elegans grows upright to about three feet in height, while Zinnia angustifolia, sometimes referred to as creeping zinnia, is much shorter at 12-18 inches, with a roughly equal spread. The Profusion series is noted for its compact size of about 18 inches, along with prolific blooms, heat tolerance and good disease resistance (powdery mildew can be a problem for many other zinnia cultivars). You’ll find orange, pink, white, and white/yellow members of the Profusion series.

Additionally, some other cultivars of note include ‘Benay’s Giants,’ the tallest of the zinnia cultivars at about four feet in height and therefore the most popular for cut-flower enthusiasts, ‘Thumbelina,’ a dwarf form that tops out at only six inches high, and ‘Zesty,’ a double-flowering form with twice as many petals per bloom.

Matthew Stevens is the County Extension Director and Horticulture Agent for North Carolina Cooperative Extension’s Pitt County Center. If you have questions about this article or gardening in general, please contact the Pitt County Extension Master Gardeners at [email protected] or 252-902-1705.