Digging the
tree's planting hole
There's an old saying about digging
a $100 hole for a $10 tree. This points to how important the planting hole can be. Good
drainage is probably the most important factor of all --- tree roots need to
"breathe" and won't tolerate prolonged soggy soil conditions that will suffocate
roots. Certain species of trees will tolerate wet conditions better than
others.
Depth:
Don't dig the hole any deeper than the root ball. The tree needs a solid
foundation to sit on, as opposed to having loose soil which may later
settle, causing the tree to sink and become crooked.
Width:
Dig the hole twice as wide as the root ball. If you are planting in poorly
drained soil with heavy clay, cut a narrow ditch out of the low side of the
hole. Backfill this ditch with looser soil that will allow drainage if the
hole fills with water. If the ground is level, consider planting the tree
with the ball elevated 1/3 of its height above the existing soil level, then
sloping up soil around the elevated root ball.
As with any
science, there is ongoing plant research that often overturns old ideas and concepts. Tree
science is no exception. A good example of this is when Dr. Shigo's research told us
"not to paint" tree wounds. If tree branches are properly removed they
have natural defenses in the "collar" area.
Likewise,
recent university research overturned some old concepts about transplanting trees.
The two most notable concepts deal with soil backfill and pruning.
Soil
Backfill
Research indicates that
trees will establish themselves better if planting holes are backfilled with the existing
soil. "Improved" backfill (topsoil, peat moss, etc) may cause roots to
want to "stay within" the existing root ball due to the differences in the
soil type.
Thinning
the crown
The old recommendation was
to thin a tree after transplanting to compensate for the loss of roots during digging.
Current recommendations call for only removing damaged or crossing branches. Some
nurserymen we know still believe in thinning.
Staking a Tree
The rule of thumb for
staking: Any tree over 6-feet tall should be staked for its first growing
season. In especially windy or harsh situations it may be necessary to stake
shorter trees as well, with the important point being that the tree is
straight when it takes root in the soil. Most recommendations call for
staking a tree so it can move slightly in the wind, the theory being that it
will develop a stronger root system with this little bit of movement. Tree
bark should be protected from wires and ties - short sections of old garden
hose work well.
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