Some late varieties may blast their buds when temperatures get warm in early spring.  This might be the variety.  I have one called Allie Habel that does that most years.  You might do a soil test just to check to see that pH and other nutrients are in the right range.  Definitely also check that the plant(s) are draining well and that heaving spring rains cause it to abort the blooms because of this.  There are many possible causes for buds not open.  Including in addition drought at bud opening with warm temperatures, fertilizing at bud swell which restricts water to the buds and may also cause buds to abort.  Is there anything different about the site than with your other plants?  That may be the clue if its not the variety. 

Thanks for your reply.  The two trees are planted as home front landscape, about 4 ft from the front of the house.  North side of house so never any sun.  Both are about 15’ tall with 6” diameter trunks. Our gutter downspouts are piped to take water away from the house, but as you mentioned, the shaded north side garden beds never really dry out in the late winter/early spring.  I’ve tested/adjusted pH, mulched, lightly pruned, etc.  I haven’t pruned them way back to solid stems for fear of killing them. But I can’t remember them ever blooming in the past 20 years - frustrating as there are tons of buds that fall to the ground....   so maybe it’s the shade/moisture and never really drying out.  Our other camellias are flourishing!  

yes the plants look healthy so the wetness might be the issue.  If you get an auger or post hole digger you could put in some holes around and fill them with organic matter  - leaves, compost, sticks etc which will help with drainage and make your soils deeper.  That might help with reducing water sitting in the area.