Contributed by: Anthony S. Aiello, Director of Horticulture and Curator, Morris Arboretum of the University of Pennsylvania

It is always a very hard thing to predict peak viewing for Cherry Blossoms, and it really depends on the weather during the 2nd and 3rd weeks of March.  “Peak” is also a hard thing to define but it usually means the height of flowering of the Yoshino cherries (Prunus × yedoensis)

There are people in Washington D.C. who study this extensively and their predictions are worth watching.  One is from the National Park Service ( and they are predicting a peak in DC somewhere between March 14-17th.  The other is the Washington Post, and their Capital Weather Gang is calling for a peak close to these dates, from March 15-19th (  

The Park Service has documented peak bloom dates since 1921, and if the DC peak happens on March 15th, it will tie for the earliest on record with 1990.

What does this mean for Philadelphia?  Generally speaking our Yoshino cherries flower about seven to ten days after those in Washington, D.C.  So, if we take mid-point of the two Washington predictions, say March 16-17th, then I would expect our dates of flowering would be somewhere around March 23rd to 27th.  This is earlier than Philadelphia’s Sakura Sunday, April 9th, but did I mentioned that it all depends on the weather?

Two caveats – there are more flowering cherries than just Yoshinos, so there is always more to see.  AND, who knows what will happen with the weather between now and the end of March?