We have a bunch of sumac on this place. We love to soak the berries for a delicious drink. This year we noticed that the Smooth Sumac blooms much earlier than the Winged Sumac.
This Winged Sumac - Rhus copallina [also called Shining Sumac] is blooming just now - a bit late. The Smooth Sumac bloomed in June.
Here's a good shot of the leaves of the Winged Sumac - notice the 'wings' that grow along the twigs between pairs of leaves. Smooth Sumac leaves don't have that.
We are at the northern edge of its range - looks like it has a Zone 5B winter tolerance.