Your mission is picking three cornstalks for your child’s 4-H exhibit. If you find stalks shooting out multiple ears, you probably think a purple ribbon is in your child’s future. But especially if those multiple ear shoots come off the main ear, keep walking. Otherwise, that purple ribbon could turn red.

“Multiple ear shoots developing at the base of the main ear on the same ear shank are definitely something we don’t prefer seeing,” says Dave Henderson, district lead for Pioneer within Indiana. “If I was searching for representative plants for the fair, I would leave stalks with multiple shoots off the main ear shank at home.”

More importantly, Henderson wouldn’t want to see them in commercial cornfields, period. If you see them while scouting, note the location. See if they’re occurring in one hybrid or multiple hybrids. The phenomenon has been observed for decades across multiple seed corn brands and multiple hybrids.

Tracking causes

Causes aren’t well understood, Henderson explains. “Though it can occur due to abundant resources related to low plant population, it can also occur due to disruption of hormonal apical dominance of the primary ear,” he says. “It may relate back to events happening at the V6 to V8 stage, even though it doesn’t show up until later.”

In fact, Henderson notes that they typically receive more reports of this phenomenon when a cold spell settles over a widespread area in June. Normally, a hormonal response prevents other ears from attempting to develop on the same shank as the primary ear. Something like cooler-than-normal weather can disrupt normal ear development, allowing other ears to initiate development on the same shank.

While this condition isn’t typically widespread, it’s not something you want to see. “Remember that it’s a sign that something didn’t occur normally,” Henderson says.

The most common occurrence of multiple ear shoots per shank are two to three small ears forming at the base of the primary ear. Usually, the main ear develops normally, and there is no noticeable impact on yield.

Other variations

Mark Jeschke, national agronomy manager for Pioneer, penned an article titled “Why do corn plants develop multiple ears on the same shank?” for the 2022 Pioneer Agronomy Research Summary. He noted that less frequently, multiple ears develop in a cluster, creating a condition called “bouquet ears.” Most don’t pollinate, although one or more may produce kernels.

Several incidences of bouquet ears were reported in Iowa in 2006 and Illinois in 2007. Researchers looked at a variety of possible causes, including drought, herbicide injury and fungicide injury. In Illinois fields, researchers observed that multiple ears seemed to grow faster if the main ear was damaged, freeing up extra sugars. But no common denominator was discovered in either year.

Insect clipping of silks on the main ear can result in multiple ears. That one is easier to prevent because there is a direct cause: insect feeding disturbing pollination. However, that’s often not the case. Jeschke suggests noting which hybrids are affected, although as noted earlier, ties to any one hybrid or brand are elusive.