Beautiful Zinnias

The zinnia is a member of the Asteraceae family and is a popular garden plant in much of the world.   Most varieties are native to Mexico and surrounding areas, mainly in North America.  They are easy to grow, bloom in a variety of bright colors, and, even though they are not native, provide nectar to adult butterflies including painted ladies and swallowtails.  (See CSU Extension Fact Sheet #5.504 Attracting Butterflies to the Garden.)

There is a perennial zinnia native to Colorado called the Golden paperflower or Plains zinnia (Zinnia grandiflora). It grows up to 8 inches tall in a clump, with long lasting golden flowers, and is found growing on the plains, deserts, and rocky slopes of eastern Colorado.  I don’t think it is found here on the western slope.  Like most Colorado natives, it requires little water and lots of sunshine.   (See CSU Extension Fact Sheet #7.242 Native Herbaceous Perennials for Colorado Landscapes.)

The non-native zinnia hybrids, also sun lovers, grow up to 3 feet tall and produce flowers in a variety of colors - white, yellow, red, orange, pink, rose –that may last through late fall. Like pansies (another one of my favorite non-natives), they can be planted earlier in the spring than other plants as they are cold tolerant and can withstand a late spring frost.   Both benefit from regular watering.  Warning: zinnias cannot tolerate a fall frost and must be covered when temperatures dip overnight, something I experienced firsthand.  It was a sad morning last fall when I discovered all my newly opened blooms had died after a seemingly not-that-cold night spent uncovered. 

Zinnias are easy to grow from seed.   Select a sunny protected garden area two weeks prior to the last frost, or when trees are starting to leaf out.  Soil should be tilled 6 – 10” and amended to produce a medium that will stay moist until the seeds germinate.  Be sure to use seed packaged for the current year, follow the planting directions on the packet, and keep the soil moist until the seedlings appear. 

My experience with zinnias has been with hybrid seeds planted in containers with good potting soil. Seeds can be planted as late as June and will produce beautiful fall flowers.  The challenge is to keep the soil moist until the seeds germinate, given our dry climate.  I was a bit lax this year with my watering, resulting in sparsely populated pots of flowers, still beautiful but not quite as colorful.  In spite of this, the colorful flowers have been a joyful addition to the garden and have attracted late season butterflies, hummingbirds, and bees.  The zinnias have given me one more chance to see the pollinators before they disappear for the winter.