Planter sizes are often determined by agency requirements. Minor refinements, within
the applicable regulations, can improve the long term prospects of landscape plants.
Narrow planters in vehicle overhang zones are rarely as successful as this one. Plants
flat enough to allow cars to pull forward fully, without obstruction, are normally
trampled almost immediately. Usually, pavement is a better option.
Planters over 7 feet in width are adequate for larger shade trees and can be irrigated
with easily maintained spray systems.
Planters between building entries and parking fields are very prone to damage from
foot traffic. Moderate widths, at least 8’-10’, can prevent vulnerable planters
from becoming trampled earth. Expanding these planters, at the expense of those in
other locations, is a worth while trade-off.
Narrow planters (under 4’) are more likely to be damaged by pedestrians and poor
maintenance practices. Where these planters have a protected location, adjacent
to a building or in a more remote area, the odds of survival are better.
Folsom Corporate Center
A typical square 8’x8’ planter island, set between two compact stalls, is a very
tight fit for a shade tree. Over-excavating the planter to a 24” depth and backfilling
with fertile soil can give trees a reasonable chance for success.
Extruded curbing, which leaves a skirt of pavement beyond the back of curb, can reduce
soil volumes excessively and leave pavement vulnerable to root damage. Cast-in-place
curbing should be used where possible in these small planters.