Iowa Native Trees and Shrubs
What’s a root bag?
Root bags, or more accurately, knit fabric
containers, are now made of polyester knit.
They work by
restricting lateral
root
growth
shortly after the
roots
have
grown through the fabric.
With the
polyester knit fabric, each opening is
exactly the same size so root pruning
becomes predictable and precise.
Lateral roots grow outward through the fabric wall with little
restriction. However, as the roots grow farther into the surrounding
soil and increase in diameter, the fabric
begins to constrict or girdle them. Root tip
dominance is lost and secondary roots
form farther back along the lateral roots.
The secondary roots soon grow through
the knit fabric, are girdled, and tertiary
roots are initiated.
This constant
restriction and girdling of roots creates a
dense root system that is harvested with
the plant and is ready to quickly establish
itself when planted in the landscape.
Why use a Root Bag?
Field growing has always produced superior trees but digging them
with a tree spade has disadvantages. Researchers have found when a
tree is dug for transplanting, as
much as 95 to 98 percent of its
root system is lost and the
capacity to absorb water from the
soil is significantly reduced which
directly affects the trees ability to
survive and reestablish itself. The
root mass often separates from the
soil during handling and transport
because there are only a few
major roots to hold the ball
together.
Container-grown trees, whose entire root system is confined to a
smooth-sided plastic pot,
quickly develop circling roots.
These roots, which never
straighten out, may cause the
tree to be poorly anchored in
the soil, and thus easily blown
over or may eventually
strangle the trunk of the tree.
Roots bags allow the root system to be harvested with the tree but
without any circling roots that may hinder re-establishment or cause
future problems. Root bags must be removed prior to planting.
Root bags marry the superior quality of field-grown trees to a healthy, self-contained root system.