Root development ceases when soil
temperatures drop below 40 degrees, so you may have to water them
through the winter if we do not have adequate rain or if the soil
remains frozen for long periods. Plants cannot absorb water from
frozen soil to replace what they lose through transpiration. This is
especially true with broad-leaved evergreens such as hollies or
rhododendrons because of their relatively large leaf surface.
Needled evergreens such as pines or spruces also continue to lose
moisture, but their needles expose a much smaller leaf surface and
generally have a waxy cuticle that minimizes moisture loss.
Deciduous plants such as hydrangeas or weigelas truly minimize
moisture loss by dropping their leaves altogether for the winter. It
is ideal to transplant them when they are dormant.
Try to move the plants to areas of your yard that fulfill their
cultural requirements. All plants have preferred environments: the
amount of sun or shade; soil texture (clay, loam or sand); soil pH
and fertility; available soil moisture; and exposure or protection
Other factors include tolerance for road salt, reflected
heat from buildings and paved surfaces, and soil compaction. The
short bibliography that follows this article provides resources
where you can look up this type of information about specific plants
in your garden.
Digging onto a heavy tarp will make
post-planting clean-up much easier!
Check the soil drainage in the parts of your yard where you intend
to move the plants by digging a hole 12 inches deep. Fill it with
water and allow it to drain completely. Refill the hole, and measure
the depth of the water with a ruler. Wait 15 minutes and measure it
again. Multiply the result by four to calculate how much water
drains in an hour. If it drains between one and six inches per hour,
the site should be fine for most plants. Less than an inch per hour
indicates poor drainage, and you will have to find a way to drain
excess water from the site or find another location unless some of
your plants are known to tolerate poor drainage. If you have the
time, it would also be a good idea to have the soil in these areas
tested for pH and nutrient content. Information on obtaining soil
test kits from Penn State Cooperative Extension follows this
article. A single kit should be fine if the areas are close
together. If not, and if the environment of the sites is very
different, take a separate test for each.
When you move them, dig as large a rootball on each as you possibly
can handle. These will have to sustain the plants until root growth
resumes in the spring. If the soil around them is dry, water them
well about 48 hours before trying to dig them. Replant them in their
new locations at the same level as they were growing before, no
deeper. Water them well, and check the soil moisture in the
rootball through the winter. Water as needed to keep the soil
slightly moist (think well wrung-out sponge), but do not kill them
with kindness, either. You can apply a two inch layer of organic
mulch around them after the ground freezes. Check them
periodically to make sure that freeze-and-thaw cycles have not
heaved the new transplants out of the soil. Roots exposed to
freezing air temperatures do not survive.
Read More About It
A., Manual of Woody Landscape Plants, Stipes Publishing,
1998, ISBN 0875638007.
A., Dirr’s Hardy Trees and Shrubs, Timber Press, 1997, ISBN
How to get Wisteria
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