Lilac buds ready to open on a cool April morning at the Huttner Weather Lab.
Our amazing spring of 2010 continues. Last Friday I was stunned to see a row of common purple lilacs blooming in Deephaven. That’s April 23rd!
According to long time Twin Cities phenologist Jim Gilbert’s Nature Notes; this would put 2010 as one of the earliest lilac bloom years on record. The average date for the lilacs to open in the Twin Cities is around May 10th, with peak bloom the following week.
Jim’s records from the Minnesota Landscape Arboretum in Chanhassen show the early Flowering Crabapple peak bloom we’re seeing now rivals the years of 1987 and 1997 when the trees also reached peak bloom in late April. Jim has observed the lilac bloom average dates have moved a full two weeks earlier in the past 40 years.
The triggers for our early spring blooms are the 4th warmest March and 2nd warmest April on record so far. This is pretty remarkable stuff when you consider that last year’s lilac blooms occurred in May close to the average date.