Why Zinnias Have Zing

Lowell Halvorson

Revenue appeal behind zinnias rests on their broad attraction to the growers. Zinnias come into retail prime about the same time as petunias, vincas and marigolds, and their market window keeps them selling into autumn as mum companions or replacements.

Seed-to-retail speed is a major part of their popularity. Zinnias offer fast turns for firms looking to convert houses to cash in short, swift cycles or tuck a crop into an idle greenhouse. A zinnia crop can go from seed to pack in about eight weeks or from plug to shipping in around four weeks, give or take the pot size.

Their appeal is also broadly national with only one weak region skirting the Gulf Coast. High summer heat in Miami and Houston splits their retail season into two parts with a summer pause.

Pictured from left to right: The core differences between Z. elegans and Z. marylandica types. Zestys are tall with big, bushy flowerheads, whereas Zaharas are shorter with flatter flowers. ■ Profusion Red Yellow Bicolor shows an uncanny resemblance to several coreopsis cultivars. ■ Several Profusion Single containers shows the color range of the Z. marylandicas—white through the warm tones into deep red.

Two species have significant commercial traction. First is Z. marylandica—the one to look at if long-lasting displays are a priority. This species has smaller flowers and more durable plants. Second is Z. elegans. If punch and pizazz are of top concern, these zinnias are meant for hot-colored container work, with big, bushy flowers in bright colors. However, if mildew troubles garden beds in the area, Z. elegans plants are vulnerable;
Z. marylandica varieties are fine.

Singles or doubles cover Z. marylandica plants heavily, with the pansy-like quality of painting the landscape with color. Flowers may be small, but there are so many that from a distance beds are lush and bright with very little green peeking through them. Plants also bury their dead, growing up and over early blooms, so they’re considered self-cleaning.

A good example is the Profusion series, introduced as Orange back in 1994 and launched as a full series in 1999. Profusion Zinnias are mounded in habit, color up from the soil and lock elbows with their neighbors to create a solid bed. Plants bloom within seven days of each other with an even growth habit.

Although it’s an old series, Profusion continues to stay new as Sakata makes running changes from year to year. For 2025, they plan to introduce an improved Double White with a noticeably bigger flower. Over the lifespan of the series, Sakata has introduced five All-America Selection winners to their zinnia lineup. That’s the signature of an active breeding program.

Zahara is Profusion’s competitor in the small zinnia market—it reflects the best of PanAmerican Seed’s breeding over the years. This series was established about a decade ago and has the complete zinnia color range in its lineup. Zahara follows the PanAmerican breeding style, so plants are more upright in growth.

Extra big flower heads with cascading petals on taller stems are the hallmark of Z. elegans, the other major commercial species. For show-and-tell there’s the Zesty series. Chain sales and the large shop-and-drop containers they favor hit Z. elegans on its strength. A long market window means effective spring, summer and autumn decor products, all grown with the typical zinnia speed-to-market.

Zinnia mixes are shifting to more sophisticated seed blends, just like the pansy mixes did a decade ago. A new series, Elegant, is devoted to zinnia mixes only and is set to release Hot Mix at California Spring Trials this year. Based on the Zesty chassis, PanAmerican plans to add some refined shades to diversify future mixes to support bowl and basket sales.

As easy as zinnias grow out, nuances still exist. First, their colors soften a little if they bloom under glass. Not much, but it’s there in the reds. Bicolors see it when the subtle changes in the greenhouse make the two-toned feature hard to see. Their full vibrancy reappears when they’re toasted outside in full, hot sun.

Orange colors can also express a little banding in the greenhouse when the light levels aren’t filling in enough pigments. For a quick check to see if the zinnia light levels are too low, look at the oranges—they’ll show the problem first.

Light levels can affect doubleness on zinnias as well. If too much of the crop expresses singles or semi-singles instead of full doubles, the light levels are too low. This phenomenon shows up more in the Z. elegans than in the Z. marylandica.

Nighttime temperatures can also affect the vibrancy of the reds. In cooler houses, the red leans towards rose; in warm temperatures, it leans hard into the red. Cool nights greatly help the color patterns.

If you grow Profusions, be sure to look at the bicolors. Both are reminiscent of coreopsis. One resembles American Dream and the other has the two-tone look of UpTick Red & Yellow. Among the Zaharas, bicolors are Sunburst and Starlight Rose in the singles and Raspberry Ripple in the doubles. GT

Lowell Halvorson is a consultant and writer in Fairfield, Connecticut, for retail and wholesale horticulture, specializing in business development. He also covers the breeding community for GrowerTalks magazine. You can contact him at (203) 257-9345 or halvorson@triadicon.com.