Use a solid reference to launch your restaurant design project. There are numerous books on the market, but one in particular that is excellent is "Successful Restaurant Design" by Regina S. Baraban and Joseph F. Durocher.
Seek out a landscaper with extensive experience in interior plantscaping. Whether she acts as an on-site participant from design to installation or just an adviser, she will help minimize mistakes that could cost your client time or money. Ask the landscaper to recommend plants and trees that are low-maintenance, thrive without a lot of light and require little fertilizer or pesticides, as they'll be in a contained environment.
Begin drafting designs and keep in mind two critical basic restaurant design principles: Your plan must complement the food and function from the back-of-house to the front. Offer the owner three choices---you'll probably wind up with a design that uses components from all three. Once the design has been vetted and approved, work with your landscaper to prepare a profile on each of the plants you've chosen to include in the restaurant's plantscape.
Choose between real and artificial plants. Before you dismiss the idea of artificial plants, check out specimens available to designers---such as preserved palms made with specially treated fronds and trunks reinforced with steel---as plants like these require no maintenance other than a regular dusting and pair nicely with other artificial plants to create natural plantscapes that are both dramatic and relaxing. If your client chooses to go the natural-plant route, ask whether she prefers to buy the plants and have her staff maintain them or rent them from a commercial nursery. The latter option usually comes with a regular maintenance contract.
Prepare a shopping list of plants. Your landscape pro may recommend Dracaena in one or more varieties, Zamioculcas zamiifolia (ZZ plant) and Sansevieria trifasciata for their pest-resistant qualities. Aglaonema (Chinese evergreen), while intolerant of cold, stand up well over time. Monstera deliciosa (split-leaf philodendron) are large, showy plants that are easy to maintain as long as you cut them back regularly.
Philodendron hederaceum (heart-leaf philodendron) and Epipremnum aureum (pothos)---both trailing plants--work nicely in places where they have enough room to creep. Pest-resistant Chlorophytum comosum (spider plant) and Spathiphyllum (peace lily) can resist bugs, and you can't go wrong with hardy Ficus elastica (rubber plant). Finally, hardy ferns can stand up to a bit of neglect while Hostas and Epiphyllum oxypetallums grow facing all four directions so you needn't be concerned about north, south, east or west-facing windows.
Visit a showroom at a major mart to choose the artificial trees, shrubs, plants and flowers you've selected. Alternately, head for a major nursery in your area with your landscaper in tow. In either case, match your interior design and list of species with available stock. This is the time to place special orders for plants that aren't available or must be custom-ordered.
Participate in the installation of your plantscape---particularly if this is the first time you've designed one. If the restaurant owner has chosen to go with natural plants, bring together everyone concerned (restaurant owner and staff) so the landscaper can instruct everyone on the care of each species in the plantscape.