Might want to try Rohslers from Allendale. They are mainly a retail nursery but unlike many other nurseries they grow many of their plants in house and they have landscape design/installation services. I have good relations with the owner and they definitely aren’t your typical nurseries where the sales people have no idea what they’re dealing with. They know their stuff and I think they would do a good job helping you out with your situation because they know so much about plants.

The Native Plant Society of New Jersey has a list of places that sell native plants. Probably some of them have landscape designers.

https://www.npsnj.org/plant_lists/Nurseries%20with%20Natives.pdf

Thank you. Those are both great suggestions.

Back to Nature in Basking Ridge is another good option:

https://backtonature.net/