Yes and no. It always depends on your geographic location and on the specific variety. Some varieties can take more sun (iron clads are popular in this area because they can withstand more sun) and other varieties can take more shade without adverse effects.

Generally speaking, in the southern states, we have to protect them from the afternoon summer sun as too much sun dries them out and bleaches the leaves. In the states close to the Canadian border, they can take more sun than they would here in Texas. Also, more sun produces more flowers but more sun also attracts lace bugs.

You may wish to contact the Rhododendron Society of Canada to see what varieties they recommend in your area:

http://www.rhodoniagara.org/

http://www.onrhodos.com/

Luis_pr, I live in the FL panhandle. Can you recommend a source for iron clads?