Philadelphus.

Mock Orange.  This is a plain, old fashioned one from my grandmother's garden.  There are newer varieties.  In fact there are Mock orange bushes growing wild all over the property.  I can hardly control them but they have no scent.  This is a pitiful display but it is my first crop of blooms since I got them.  They have a very heady scent, nearly overpowering really, so plant then at some distance from your hay fever victims.  Some varieties are available with a stripe of red in the throat, but this is my favorite.  I don't ever see this in nurseries.  It is a shame because once it is established, there is nothing to do but enjoy it.  After all, who would want to control something this wonderful.  However, standard pruning practices will improve an older plant.  Remove 1/3 of older branches at the ground each year.