Today most new homes in subdivision type neighborhoods built by 1-3 different builders belong to a homeowners association. Similar to a condominium HOA they can have some control of your outdoor living space. Often homeowners are not aware of this legal agreement they agreed to abide by at the closing of their new home. The HOA bylaws can vary depending on how it was written. Usually they have some control of the outside of your house. Even though you own your property the HOA often has guidelines to control activity outdoors. One purpose of the guidelines is to maintain harmony of the neighborhood.
If you choose not to abide by your HOA agreement be prepared to go to court. Be sure to check with your HOA if your new landscape needs to be approved by them first. Sometimes the HOA has a board member(s) who handles that type of approval. Other times the HOA board has hired a management company that will handle that for them. Either way, you (NOT YOUR LANDSCAPE CONTRACTOR) are responsible to honor your HOA agreement.