Re: Berms

Donna, You might also want to consider some of the many plants that like wet feet, even if you do use a berm. You would be surprised how many nice ones are out there. I bet a Button Bush (Cephalanthus occidentalis) would love that spot even without a berm!
Cathy

On Tuesday, April 8, 2003, at 10:43 PM, Marge Talt wrote:

Wouldn't worry about it, Donna.  If the berm was at least a couple of
feet high, the trees and shrubs are either sending roots sideways, if
they find the underlying soil too wet, or enjoying the deep moisture
some of the time.  Most trees and large shrubs have the bulk of their
roots in the first foot of soil.  Some send down tap roots, but these
are primarily anchoring devices...and some will send other anchoring
roots farther down.  But, feeder roots are almost always in the top
layer of soil, which is the one you need to worry about as far as
drainage is concerned.

Problem with planting into poorly draining clay is when a hole is dug
for the plant without breaking up the soil in a sufficiently large
circle around the planting spot.  This creates a bathtub into which
water drains and from which it does not drain fast enough.  The roots
are pretty much confined to this tub because, in the digging of same,
the sides of the hole were no doubt smoothed out and possibly
amendments were mixed into the planting hole and the roots can't or
are reluctant to try to penetrate into the surrounding natural soil.

In clay soils, with no hardpan or rock layer immediately under, the
key is to use a digging fork and dig a circle of soil at least three
times the rootball diameter to the depth of the rootball.  This area
should be well broken up and then the hole for the plant scooped out.
 This allows water to drain all around the plant and makes it easier
for plant roots to expand out into the surrounding soil.

Unless the spot has standing water for days after rains, even clay
that drains slowly will drain with this method.

Hardpan, shallow underlying rock areas and swamps are another
matter:-)

Marge Talt, zone 7 Maryland
mtalt@hort.net
Editor:  Gardening in Shade

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