I found this at the following website and thought it was pretty interesting.
http://gardening.about.com/od/organicgardenin1/a/Phenology.htm
Quoting:
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
