To further illustrate:

-- If you dug a hole one foot deep in the back yard of my parents' house and
filled it with water, two weeks later it would still be half full. (They
eventually had a contractor put in a drainage system so the yard would not
be a swamp for three days after every heavy rain.)

-- If you do the same in my current back yard, five minutes later the water
will be gone. (In some areas it will drain away as fast as you can pour it
in.)

This helps give an idea of how much soil drainage can vary, depending on the
soil type.

Utopia in Decay
http://home.comcast.net/~kevin.cherkauer/site/

Kevin Cherkauer


To From: "Kevin Cherkauer"
Newsgroups: rec.gardens
Sent: Monday, June 09, 2008 7:31 PM
Subject: Planting in a Mound

It could depend on the soil types and local rainfall patterns and amounts.
If the areas had heavy clay soils and reasonable rainfall, they might have a
problem of soggy soils with bad drainage causing root rot. (Such as where I
grew up in western NY state.) Planting in a raised mound helps alleviate
these problems.

On the other hand if the soil drains well and/or there is not good rainfall
year-round, planting in a depression can help maximize the amount of water
captured for the plant from what rain there is. I think this is the more
common case in states like California.

You say you are in the CA Mediterranean climate. I assume that means most of
your rain is in the cold half of the year. (The same rainfall pattern we
have here in the Willamette Valley of Oregon, although it is not warm enough
to be a "Med" climate here.) This is a very rare rainfall pattern in North
America. Most of the rest of the lower 48 get most of their precipitation in
the warm half of the year (when the plants really need it!). Thus different
regions have different sorts of challenges. :-)

Utopia in Decay
http://home.comcast.net/~kevin.cherkauer/site/

Kevin Cherkauer


"David E. Ross" wrote in message
. ..
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.

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening pages at http://www.rossde.com/garden/