As you watch the rivers swell with the melting snow of winter and you feel the temperatures  warm with the onset of spring, know that many plants and animals are paying close attention to these factors as well. The science behind these correlations determines the timing of many events in the environment.   Phenology is the study of these events, specifically the relationship between life-cycle events of plants and animals as they are influenced by climate, habitat, and seasonal change.


Phenology is derived from the Greek word phaino meaning “to show, to bring to light, or make appear” indicating its principal concern with the dates of first occurrences of natural events in their annual cycle.  Examples include the date of emergence of leaves and flowers, the first flight of butterflies, and the first appearance of migratory birds,  as well as the date of leaf coloring of deciduous trees in the fall, the dates of egg-laying of birds and amphibian, and the timing of the cycles of honey bee colonies. Most of us are novice phenologists as we often notice when the birds return, our bulbs are up, and the trees leaf out.

You can time many of your gardening practices by observing these events, whether it be planting seeds or watching for destructive insects.

Here’s a great chart from

Plant peas When forsythia & daffodils blooms
Plant potatoes When 1st dandelion blooms
When the shadbush flowers
Plant beets, carrots, cole crops, lettuce and spinach When lilac is in first leaf
Plant beans, cucs and squash When lilac is in full bloom
Plant tomatoes When lily-of-the-valley are in full bloom
Transplant eggplant, melon and peppers When irises bloom
Plant corn When apple blossoms start to fall
Seed fall cabbage and broccoli When catalpas and mockoranges bloom
Seed morning glories When maple leaves reach full size
Plant cool season flowers (pansies, snapdragons…) When aspen and chokecherry trees leaf out
Watch for:
Eastern tent caterpillars to hatch When crab apples start to bloom
Gypsy moths hatch When the shadbush flowers
Squash vine borer eggs are laid When chicory flowers
Mexican bean beetle larvae hatch When foxglove flowers open.
Japanese beetles arrive When morning glory vines start to climb