Sidewalk and Planter. The Sidewalk-Tree Planter public frontage attempts to balance walkability with streetscaping. Street trees are located in planters that can aid in stormwater infiltration as well as provide additional area for tree growth and supplemental plantings. The clear walkable zone should be a minimum of five feet wide. Trees should be placed a maximum of 40 feet on center within five foot by eight foot minimum planters. Supplemental plantings in planter may include grasses, low shrubs, perennials, and groundcovers.