Your trees are young. They probably just need more time. Fertilizer will not make a difference.
Dogwoods are forest trees that like to grow in organic soil and partial shade. You can improve the soil around it by applying compost. Also, if you mulch around the tree, it will decompose and improve the soil, too.
Be sure to keep mulch off the tree trunk. Pull it back at least 3-4". And make it no more than 2-3" deep. As years to by, the soil will improve as the ants and worms mix the old clay soil with the organic matter.
Your tree is not very straight. You might want to stake it upright now otherwise it will only get worse--one year should do it. Do not leave cords on more than one growing season.
Water it during droughts--which includes spring and fall droughts.