Horticulture Principles and Practices

pennsylvanica), hackberry (Celtis spp.), American elm (Ulmus Americana), poplar
(Populus spp.), willow (Salix spp.), sumac (Rhus spp.), and silver maple (Acer saccharinum).
Species that are not tolerant of transplanting include walnut (Juglans spp.), oak
(Quercus macrocarpa), and buckeye (Aesculus spp.).
17.14 PLANTING TREES
The success of a transplanted tree seedling depends on the timing of planting, seedling
preplanting preparation, soil preparation, and planting technique, among other factors.
17.14.1 TIMING
Spring offers the best conditions for planting many tree species. The conditions at this
time provide adequate moisture and warm soils for plant root establishment and growth.
The relatively cool temperatures of spring minimize moisture loss through transpiration
and thus reduce the incidence of transplanting shock. The cool temperatures of fall
(in areas where winters are mild) also provide good conditions for planting trees. The
limitation to planting under this condition is frozen soil. Many deciduous and evergreen
broadleaf trees as well as conifers may be planted during this period. Planting in summer
is most challenging because of the high temperatures and intense sunlight that
induce rapid drying of plant tissue. Some container plants may be planted during this
period but will require great care for success.
17.14.2 LOCATING PLANTS
Trees live for a long time in the landscape. Mistakes in locating them can be costly.
Locating plants in the landscape should be done very judiciously, taking into account
structures like sidewalks, pavements, light posts, buildings, and the adult plant size and
form. Trees should be located where they will have ample room for both root and crown
to develop fully. The light conditions, soil pH, and soil moisture are critical factors to
consider as well.
17.14.3 DIGGING THE HOLE
Some general guidelines should be observed in digging a hole for planting trees. First,
the hole should be large enough to contain the plant roots without the need to squeeze or
pack them tightly. There should be ample room around the roots for soil to be added. The
hole should be at least 12 inches wider than the ball of roots. The depth of the hole should
be such that when the plant is set, the original soil level on the plant is maintained after
filling the hole with soil. It should be about 6 inches deeper than the soil ball around the
roots. The topsoil should be carefully piled up near the hole in a separate heap from the
subsoil, which is called the backfill soil. This practice may not be possible when a tractormounted
power take-off is used to dig the hole.
17.14.4 PLANT PREPARATION
Bare-root plants should be sent to the field in a container of water to avoid drying roots.
The roots are then carefully pruned before setting in the hole. In container plants, the potbound
roots should be straightened and spread out before placing them in the hole.
17.14.5 PLANTING
Bare-root plants need to be held while setting them in the hole. First, some backfill soil is
placed in the hole. The plant is then held such that the crown is slightly above the soil level,
and the hole is refilled with topsoil or, as some growers prefer, amended soil (soil mixed
with organic matter and sometimes fertilizer). After filling, the soil should be packed firmly
by tamping with a foot or stick, making sure the trunk remains erect (Figure 17–8). In the
Backfill Soil
Topsoil dug out of a hole
and used to fill it during
seedling transplanting.
17.14 Planting Trees 529