Cherry & Plum Trees Have Few Flowers

I have 2 Mount Fuji Cherry trees and one plum tree planted about 4 years ago that look very healthy with beautiful bark and nice leaves. However, each year I only get a few blossoms which fall after about 2weeks. Not sure why this is happening. Perhaps the soil is not great or they're not getting enough water? Should I maybe try those stick fertilizers to plant at their base?
Thanks

 

Maybe try a light pruning (<25%) early next spring. Sometimes the stress can induce flowering.

 

Don't do anything until you find out what the problem is.