The lilacs are blooming!
I have an old lilac in my community garden plot. Its a great bush for telling when to plant. It buds up when its time to plant early seedlings (broccoli, cabbage, lettuce, beets and onions) and seeds (peas, fava beans, carrots, dill).
And when it blooms, its time to plant the warm weather crops. Tomato seedlings and bean seeds. And get the beds ready to plant corn seeds and melon and squash seedlings.