At the same bog where I encountered Rhodora flowering in mid-May, the pink flowers of Bog American-laurel (Kalmia polifolia) could be seen alongside. I find this short shrubs' flower buds, which look like crown-shaped confections, to be even more attractive than the open flowers. The red fruit capsules which follow the flowers are also snazzy (see bottom photo).
Flower type: 5 Regular Parts (5--)
Plant type: Shrub (55-)
Leaf type: Entire (552)
Just a couple more questions. Are the leaves evergreen? Yes. Are the leaves under 1" long? No. This combination takes you to page 292, where you can identify your mystery plant as Kalmia polifolia (Pale Laurel is the common name given), another native member of the Heath (Ericaceae) family.