Hello!

This definitely looks like a challenging planting site: shallow soil, poor drainage in winter or over-drying in the summer, and salt retention all adversely affect plantings. There's also zero natural protection from wind in this planting strip. All the yellowed foliage will be eventually shed; there's nothing one can do to make it green again.

Owner can add compost and try to maintain a good watering schedule during the growing season in order to relieve some of the future stress on the planting; that said, this style of planting is a maintenance chore, and hard to keep successful. Depending on what the owner's plans are for maintaining this area, they may want to rethink the planting style, remove the evergreens and replant with shorter low-care deciduous shrubs with shallower root systems, such as as dwarf Korean lilac or Knock Out rose, which are inexpensive and widely available through nursery trade.