Unfortunately, the University of Md. Extension Service does not provide landscaping services.  You may want to ask friends, neighbors and relatives for names of reliable landscaping services, especially if you like their yards, or look online for local companies!

However, the Extension Service does strongly recommend 'conservation landscaping' or 'Bay Wise landscaping' with the specific goal of reducing pollution and improving the local environment.  And from your question it sounds like you are already headed in that direction. Some of the basic steps of this type of landscaping begins with reducing lawn area and replacing the lawn in several areas with locally native trees, shrubs and perennial plants.  Native plants are adapted to local soil and climate conditions and may require less fertilizing and watering; they are often more insect and disease resistant; and their berries provide food for the birds.

You can begin this work with your idea of a colorful walkway to the mailbox, as well as creating garden beds around some of the saplings you've planted.

Following is a link to the Md. Extension Service website pertaining to native plants which should give you some ideas.

https://extension.umd.edu/programs/environment-natural-resources/program-areas/home-and-garden-information-center/yard-and-landscape/native-plants-home-garden

There is a booklet available from the US Fish and Wildlife Service called "Native Plants for Wildlife Habitat and Conservation Landscaping which lists many types of native trees, shrubs and perennials for sun and shade. https://www.fws.gov/chesapeakebay/resources/native-plants.html

It is difficult to plan a landscape if you have frequent deer visitors, but there are native plants that are deer resistant -  https://extension.umd.edu/resource/deer-resistant-native-plants. You may also want to consider fencing a small area of your yard.  Several deer resistant trees I recommend are Hollies and Red Cedars; and a wonderful native ornamental bush that attracts butterflies, resists deer, and likes part shade is Sweet Pepperbush (Clethra ainifolia).

One last suggestion: come visit the Baltimore County Master Gardeners' Demonstration Garden at the Md. Agriculture Center and Farm Park, 1114 Shawan Road, just west of I-83.  There is a Bay Wise Garden there as well as a pollinator garden, vegetable garden and others!  The gardens are to the left of the parking area.

I hope this is helpful.  Debbie

Glad it was helpful.  Debbie