Question
What causes,corn to grow as high as11 feet and six inches tall, with only one mature ear of corn. A couple years ago, one,stalk had six ears of corn on it.

Answer
Earnest, the height of the stalk has nothing to do with how many ears grow per plant.  Most varieties of corn, regardless of height, grow one larger mature ear and a smaller ear a foot or two below it. The degree of pollination will determine the size of the kernels and how full the ear grows.

Although I have never experienced one stalk growing six ears, it probably was a mutant plant.  With today's hybrids, some of the seed can produce strange characteristics. That's most likely what happened.

I hope this answered your question. Please write again if I can ever be of assistance.

Regards,

Mike