Say Plant Phenology ten times really fast

Okay, so maybe saying Plant Phenology ten times really fast isn’t the most productive use of your linguistic skills, but if you did want the challenge – wouldn’t it be nice to know what Plant Phenology is?

Simply put, phenology is the study of the timing of recurring biological events from season to season – for both animals and plants. Plant development each spring, from bud development to leaf emergence to spring flower are all timed in sequence based on environmental factors that can be measured and used to predict when these events will occur.

Why is this so important? Those who are observant, and most gardeners and landscape service providers know which plants flower first in the year. Most everyone knows that spring has arrived when the forsythia is blooming. What’s interesting to know is that white pine weevil insects also emerge at about the same time. So, those interested in managing potential insect problems proactively can use a tool like a Plant Phenology chart to know that when the Japanese Pieris is in full bloom, that the white pine weevil emergence will be coming soon.

The actual dates that each plant emerges from year to year is not tied to a calendar we keep on our desk. There are seasonal fluctuations which affect the timing on the calendar from year to year – so we can’t say that on April 1st we should be looking for white pine weevil. By using the Plant Phenology chart we can use the flowing of plants as visual indicators of when we can expect eggs to hatch or adult insects to emerge of certain insects which allow us to monitor pest populations to see if some action is required.

Okay – wow, that sounds like a whole lot to take in. For most homeowners using this tool is not necessary as you may depend on a professional to manage your landscape. But for those gardeners who are continually frustrated and feel as if they are a step behind because you can’t constantly monitor for insects and catch them all – a tool like this is invaluable because it allows you to be proactive.

It is important to know that the plant phenology chart available for each area is a guide and may fluctuate from plant to plant and from area to area. Because plant and insect development is based on growing degree days (GDD), a measure of the accumulated number of degrees over the average baseline, the actual temperature measurement varies from area to area and may even be affected within an area due to microclimates. The age of the plant, moisture of the soil and other factors can also affect the timing of certain biological events.

The Ohio State University Extension office provides a plant phenology listing that is updated with current growing degree day information by zip code.

More information can be found here about how GDD are calculated and some of the challenges that may occur when using this tool. The June 19th edition of the Buckeye Yard and Garden Line newsletter addressed GDD - the issue is located here.