I was wrong on Friday (see the previous post)–the crocuses were up, at the same time as the hazelnuts began to bloom. Knowing which plants bloom at the same time is an example of phenology, the study of cyclic and seasonal variation in the natural world. Knowledge of phenology is very important to horticulturists, naturalists, environmental scientists, biologists, botanists, and people in many other fields of endeavor. For example, it helps me predict both when aphids might appear on specific plants and when ladybugs will arrive to take care of them. And this knowledge prevents me from reaching for a spray can to zap the aphids, because it tells me that nature will take care of the problem for me. You can learn more about phenology and watch spring unfold across the United States at this website.