On Jun 9, 12:01�am, "David E. Ross" wrote:
My wife and I recently returned from a vacation that took us to
Pennsylvania, Maryland, and Washington DC. �While there, I noticed that
many trees and shrubs are planted on top of small mounds (about 2-3 ft
in diameter and 1-2 ft high for a shrub, larger for a tree).

No, these were not planted "at grade" and then soil mounded around them.
�I could tell by looking at the base of a tree or shrub that a mound was
formed first and then the plant was placed at the top of the mound.

Why is this done? �We don't plant things that way where I live. �Here,
some trees and shrubs are actually planted in a slight depression (an
"anti-mound") to catch water and prevent run-off during irrigation.

In some areas there're the opposite conditions. Mounding is a way to
circumvent drainage problems; either standing water or the ground is
too porous. The most common reason mounds are used for planting in
those areas is that there's bedrock or a shale bank just below the
surface... in many coastal areas there's only sand, the ground perks
so well that were not for mounding even small plants wouldn't
survive... could be clay, or a high water table too. When properly
constructed a large saucer shaped depression is scooped out and the
mound is built up over a large enough area that it's not very
noticable... obviously the mound should be appropriately sized for the
planting when it reaches mature growth... what you noticed are
probably mounds that were skimpily constructed without taking into
account that the plantings would grow, or were purposely meant to be
berms to simulate outcroppings but not properly planted.