Zinnias provide a summer of color
Zinnias are one of the most popular, easy to grow, flowering annuals for gardens. Native to Mexico, the Southwestern U.S., Central and South America, they belong to the Aster family.
The plants (Zinnia spp.) were brought to Europe in the 18th century and were first described by Dr. Johann Gottfried Zinn, for whom they were named. However, zinnias did not become widespread until the 1920s when they were popularized for gardens because they came in so many different colors.
Of the 17 known species, Zinnia elegans and Z. angustifolia, are the two best appreciated for their ornamental characteristics.
Z. elegans is the most extensively cultivated for annual garden use. Plants typically grow 1 foot to 3 feet tall on upright, hairy, branching stems with coarse leaves and large flowers.
Z. angustifolia is a low-growing type used in hanging baskets, borders, and containers, as well as mass plantings. Their leaves are small and narrow and size ranges from dwarf (6 inches) to tall (3 feet). The Profusion and Zahara series are popular hybrids of these two species.
The creation of hybrids and cultivars allows home gardeners many choices in flower styles, colors, shapes and sizes. Most varieties are prolific bloomers, and flower continuously from summer to frost. This long bloom season makes them excellent for landscape color in mixed plantings or for cutting gardens.
Zinnias are one of the best annuals for attracting pollinators, especially butterflies. Interplant zinnias between rows of vegetables or as a border around vegetables to attract more pollinators to your garden.
There are a few guidelines available for attracting butterflies to your yard using zinnias. Generally, the taller varieties are better than dwarf or compact cultivars, and those with wide, flat blooms provide a larger landing surface.Flowers should have prominent yellow centers (disc floret); double bloom varieties make it difficult for butterflies to access nectar.It is also possible that some varieties attractive to butterflies produce a larger quantity of and/or better-quality nectar than others.A few of the suggested zinnias to grow in a pollinator garden include: Zahara, Benary's Giant, Tall State Fair, California Giant, Cut and Come Again, and Lilliput. One dwarf variety, Dwarf Profusion, has also been found to attract butterflies.Butterflies commonly attracted to zinnias include swallowtails (Papilio spp.), monarch (Danaus plexippus), painted and American ladies (Vanessa cardui, V. virginensis) and red admiral (V. atalanta).Zinnias are low maintenance beauties that prefer full sun (at least six hours/day) and tolerate many soil types and conditions. Because they originated in arid regions, they love hot weather and are drought tolerant, but should be watered regularly.Plantings should be fertilized at least twice during the growing season using a balanced granular or water soluble 20-20-20 fertilizer, or a slow release fertilizer at the time of planting.Give each plant plenty of space when setting them out as the hairy stems of zinnias are susceptible to powdery mildew. The mildew will cause a dull, whitish coating on the leaves and stems. Watering in the morning and at the base of the plant will reduce the incidence of mildew. There are also mildew-resistant varieties.Deadhead (remove spent flowers) regularly to extend the bloom time. Allow each plant to grow into its natural side-branching form to shade out weeds.No matter what type of zinnias you choose to grow, or how you choose to grow them, you will be rewarded with a bold, colorful flower garden full of blooms to enjoy all summer long.
Mary Alice Koeneke is a Penn State Extension Master Gardener of Butler County.
