Ask Mr. Smarty Plants

Cotinus obovatus (American smoketree) is native no farther north than Kentucky, and is hardy from USDA Hardiness Zones 5 to 8.  There is another tree with the common name "smoketree," Cotinus coggygria (smoketree) which is native to Southern Europe, Central China and the Himalayas,  This USDA Plant Profile shows this tree growing in Pennsylvania and as far north as some provinces of Canada.  The expertise of the Lady Bird Johnson Wildflower Center is limited to the care, protection and propagation of plants native not only to North America but to the area in which they are being grown. 

To help you answer your own question, did this tree bloom previously, or are you saying you have had the tree two years and it hasn't bloomed yet. Many trees do not bloom until they have several years of maturity. Blooming takes a great deal of energy from the plant, and they need to devote that energy to leaves and roots the first few years. If it has bloomed previously for you, what has changed in the environment of the tree during the past year? Too much fertilizer, especially too much high nitrogen fertilizer like you put on lawns, will produce lush leaves and few or no blooms. Perhaps this website from Floridata, Cotinus coggygria, will give you the answers you need.