The forsythia are blooming here in Chicago, They appeared to pop open overnight. It's quite possible with these extremely warm temperatures all week. It has been in the high 70s and it isn't even officially spring yet. Forsythia shrubs are known for their early bloom and bright yellow splash of color. The flowers bloom before the leaves appear, making for a showy display.
Besides being a bright yellow indicator of spring (normally), the forsythia clock is useful for planning other garden tasks. It indicates the soil is at least 55 degrees. If needed, you should use crabgrass preventor now since the seeds are ready to germinate. Crabgrass must be treated with a pre-emergent in early spring even though the evil weed shows up in summer.
And forsythia blooms mean it is time to prune your roses. Best to forgo fall pruning and do it now while the leaf buds are starting to swell. Don't forget to feed them now too with a rose fertilizer and maybe a shot of seaweed or fish fertilizer. If you don't have forsythia around you, look for the crocus blooms.
Traditionally, you can plant peas on St. Patrick's Day. Of course the weather varies year to year. It was cold this time last year and my peas took awhile to emerge. But when the daffodils bloom, it is time. Mine opened this week so the peas went in today.
Lilac shrubs are supposed to tell time for several tasks depending on their progress. Plant lettuce when they leaf out, beans when in full bloom, and cucumbers when blooms fade. I am going to test it out this year.
These are easier reminders for me than remembering to check a calendar or the seed pack notes. And likely more accurate season to season. I can be gently reminded daily by Nature herself as I walk my dog or do my gardening.