Do you know what type of soil is in your yard? One reason your shrubs may not be taking as they should be is that they may not be native to your type of soil. New Jersey soil has a lot of thick clay in it, which makes it a poor environment for any shrub that was grown in looser sandy soil. Shrubs have a favorite type of soil, just like you have a favorite snack!
Where you want to put a tree or shrub may help define what type of tree you get. Some trees may not survive in the temperament of your location. Soil texture, wind damage, access to water (or too much thereof), and warmth requirements are all concerns to keep in mind.