Recommendations from a Recommendations
from a Nurseryman
By Phil Reilly
you ever wondered why some
recently planted, healthy-in-thepot
plants die before becoming
established in your gardens?
You’d be surprised at how many of our
nursery’s customers raise their eyebrows at
our explanation for most premature plant
deaths – improper planting! They are even
more astonished when we suggest contrasting
soil types as a leading contributor to their
plant’s demise. These two possible causes are
linked and this article draws the connection.
First, let me present an invisible physical
phenomenon that naturally exists at the
junction of two soil types. A microscopic layer
of air is often found where two distinctly
different soil types meet. This air layer is more
evident after adjacent and distinctly different
soil types have been dried out and then rewetted.
If one medium is selectively and
incompletely re-hydrated, the layer of air acts
as a barrier to conduction of moisture
between the two soil types. This’ air barrier’
naturally stops the capillary, or wicking, transfer
of water molecules to adjacent soil particles.
Now consider that your ready-for-planting
plant is likely growing in a medium rich in peat
or bark and your garden soil composition can
range from sticky clay to beach sand. In
general, the greater the contrast between the
two, or the greater the extreme in the
condition of your garden soil, the more
difficulties you will have. The two distinctly
different soil type juxtaposition, with
associated ‘air barrier’ creation possibilities,
about to be created!
Second, consider what happens when a
delicate root is exposed to air. If there is
enough time for the response, the root will
innately turn away from unfavourable
conditions (e.g. an air layer) and seek out
more favourable environments. If response
time is inadequate, root tips simply dry out.
This happens all the time in pots in the
nursery. Roots do not grow beyond the pot
walls even if they are fibre pots that allow
roots to penetrate their walls upon
appropriate planting. The roots turn inward
and continue growing in a circular pattern
within the more favourable soil conditions
in their pot. In the transplanting situation,
the existing potted root mass may be the
most favourable environment if it continues
to be pampered by the gardener through
selective watering. It is so easy to
unwittingly encourage roots to stay within
the confines of its former home rather than
encourage them to venture out into their
new, more uncertain, and likely ‘tougher’,
garden soil home.
Let’s return for a minute to moisture
phenomenons common to soil-less mixes.
Even if covered with a layer of soil or mulch,
they dry out faster than most garden soils.
This is accentuated during periods of
intense sunshine or moisture-sucking winds.
At the other extreme, soil-less mixes also
absorb and hold more moisture than many
garden soils. In the home garden this overmoist
condition is often of our own creation
- water conservation objectives lead us to
selectively water new transplants and to not
water the surrounding soil!
With the preceding explanations of what
can happen in soil environments,
what do we recommend?
Dig a Wide Hole
First, roots need more than a ‘just big
enough’ hole to be prepared to
accommodate their developing root system.
This is especially true in clay or rocky soils
and for larger plants such as trees and
shrubs. Developing plants need room to
grow extensive lateral roots systems that
provide nutrients and moisture for growth.
We suggest plants need three times the
diameter of the purchased pot for
successful establishment. Planting holes
need be just deep enough to accommodate
the root mass.
No Gravel Please
Gravel should not, under any
circumstances, be placed as a discreet layer
in the bottoms of beds or individual holes to ‘improve
Remember the air barrier phenomenon just presented. Gravel
separating soil types magnifies the
phenomenon. As well, in rainy weather, a
gravel layer on top of a clay soil creates a
bowl for water to pond in and prevents
healthy root growth.
When you build each garden bed, use the
best grade garden topsoil available. The
addition of aged compost, when building the
bed, will increase moisture retention,
increase organic nutrient supply, and
increase aeration levels for long-term
healthy root growth. Aim for a compost to
soil ratio of 1:3 (i.e. 25%). We use seashell
compost as we’ve had some horrid
experience with salt-laced mushroom
compost killing plants. Another alternative is
quality ‘triple-mix’ – a premium garden
consisting of topsoil, peat moss and
manure/compost, but again there are
differing qualities of ‘triple-mix’, so it’s
to use a known and reputable source.
Build a Raised Bed
In clay soil areas especially we suggest that
gardens be constructed as raised beds to
provide for adequate spring and post-rain
drainage. Beds need only be raised 3-4
inches (7-10cm) but up to 12 inches (30cm)
for wide beds if achievable. They do not
need to be contained – just slope the sides.
Before placement of topsoil or triple-mix on
clay areas, it is a good idea to open up
drainage channels for improved drainage.
Plunging a garden or 3-tined hayfork into
the clay, under the new bed location, will
assist water to percolate into the soil.
Dozens of tine holes per square meter is
not too much!
Time for the
Use a roto-tiller to blend the first 2 inches of
topsoil/triple-mix in with the existing soils.
This helps overcome potential air barrier
phenomenon problems from arising.
Following this blending, the balance of
topsoil can be placed on the garden. In
sandy and rocky areas, imported quality
garden soil can be simply mixed in with
existing soil to better the overall soil quality.
The deeper the prepared bed the better –
24” (60cm) is not too much.
At planting time thoroughly soak planting
holes and the soil around the planting area.
The plant to be planted should be soaked to
the same degree as the receiving soil to give
uniformly moist conditions to roots and the
soil. If the root mass is at all dry, immerse
the root mass in a bucket of warm water to
achieve complete hydration of peat and
Feed the Roots Please
Place a non-burning, root-stimulating
fertilizer, such as powdered bone meal, in
the bottom of each planting hole after the
soil soaking procedure. Place a thin layer of
soil over the bone meal to separate tender
root hairs from the bone meal. The roots
will grow into the bone meal reserve to get
the root-strengthening nutrition. We
caution against using water-soluble
fertilizers, such as those with a 10:52:10
formulation, in the soil-soaking or watering
stages. These fertilizer salts can damage
root hair growth. In addition, the elevated
phosphorus level (middle number) reduces
development of beneficial soil-borne fungi
that colonize developing roots to make
them stronger and more drought resistant
(see ‘Plants Crave Fungi’ in the Spring 2004
issue of The Epic Gardener for details on
Doctor the Roots
At the moment of planting, each plant
should be inspected for the need to ‘doctor’
its root mass. Lightly root-bound plants
need circling roots to be gently teased or
washed apart to break away from their
circling pattern - a pattern they’d continue
after planting. If the roots are tightly bound
around the periphery of the root mass,
make about four - quarter inch (0.5cm)
deep incisions, using a sharp knife or box
cutter, into the root mass to stimulate new
growth outward into surrounding soil. If few roots protrude
from the potting medium,
about 1/3 of the medium should be teased
or washed off the root ball to expose the
roots to their new garden soil. In all cases,
the objective is to assist roots make
immediate contact with their new growing
medium and negate any limiting ‘air barrier’
condition from arising. Do one plant at a
time! Don’t leave delicate roots exposed to
the air, where tender root hairs can
desiccate and quickly die, for more than a
minute – even that can often be too long. If
you are delayed in planting for any reason,
cover un-potted plants with a wet towel or
place them in a bucket of water to keep the
roots from drying out.
No Stomping Please:
Settle for Water
At the soil backfilling stage, loosely place soil
around the prepared-for-planting root
mass. In addition, we recommend a fungal
supplement be added to the backfilling soil
to help roots get established. Some retail
nurseries (ours included) are pioneering a 5-
year warrantee on trees and shrubs that use
the appropriate fungal supplement at
planting time (see our web site www.rcgardens.ca for
details). Resist the
temptation to punch, pound or stomp the
soil. Compacting the soil around the root
mass reduces needed air spaces for
optimum root and fungal development. To
settle the soil around the root mass, gently
provide copious amounts of water to
eliminate large air pockets and bring roots
into direct contact with soil particles. Aim to
establish a slight depression in the soil, or
create a 2-3 inch (5-7cm) raised ring of soil,
around fresh transplants to catch available
water (rainfall or applied) and direct it to the
developing root system. To reduce
evaporation loss due to wind and sun
exposure, apply 2-3 inches (5-7cm) of bark
or other decorative mulch around the
No Fertilizer for
Do not apply water-soluble fertilizers
around the planting area at planting time.
Wait about a week, allowing roots to
become established in and accustomed to
their new environment, before adding any
additional fertilizers. When choosing
fertilizers, organic fertilizers are much better
because they favour the development of the
myriad of soil-borne organisms that support
healthy root growth.
Other Steps to Success
The above planting tips will give plants the
best chance to become successfully
established and be better able to withstand
slight stresses. Are there other chores
conducive to successful plant establishment?
Keep them Moist
For the first month or two, assure that a
uniformly moist soil is maintained, at all
times, around establishing plants. Your local
environmental and soil conditions,
particularly during the summer, will dictate
the frequency of adding supplemental water.
Ideally the top 2-3 inches (5-7cm) of soil
should become dry looking (not parched)
before irrigating again. This encourages the ‘breathing’ of
the soil – it
allows air to be
sucked into the soil to refresh needed
oxygen for optimum root metabolism. With
the use of moisture-retentive mulches you
may have to peel back the mulch periodically
to monitor moisture conditions. An
inexpensive moisture probe, available at
most garden centres, is a handy indicator
tool that can assist in determining the proper timing
of adding water to the soil.
Reilly and family operate a specialty nursery,
Reilly’s Country Gardens, in west Ottawa. Their
nursery features an acre of demonstration gardens
showcasing over 1800 varieties of perennials –
many of them bought from Epic Plants.
Phil and his wife Carole are again leading a 5-day
bus tour from Ottawa to the Niagara area. Visit
for tour details,
sheets and photo galleries of their nursery
specialties: peonies, hostas, ornamental grasses
and, new in 2005, pond supplies and aquatic plants.
Trees and shrubs likely to sway in windy periods should
be provided with
supports to keep them stationary during their root establishment
mass movement, occurring during windy periods, ruptures
trying to get established in the soil. Typically three
guy wires (or ropes) per
tree, with protective rubber hosing secured, but loose
fitting, around the
trunk, are installed and brought to the ‘just tight’ stage.
Attach the wires or
ropes to posts or anchors, arranged in a triangle, making
sure that they do not
damage the tree’s bark.
Removal of the support ropes or cables should be done
as soon as the tree is well
rooted – usually in the second season. Stronger
trunks develop in trees allowed
to sway with the breezes, but firm root establishment
is the priority concern.
Pamper Them for Winter
As the first winter approaches, ensure plants (especially
late-planted ones and
those in exposed locations) have thoroughly moistened
soil so that your plants’
late fall and winter moisture needs are met. Even though
the trees have lost
their leaves or perennials have died back from frost,
the roots will keep
growing right up to complete ground freeze-up. A winter
soil mulch (such as
evergreen boughs or straw) should be applied, to within
six inches of
tree/shrub trunks, to moderate soil freeze-thaw conditions.
mulch should be kept about six inches away from tree trunks
bark-gnawing rodents from nesting and feeding on your
A protective blanket for trees and shrubs likely to be
exposed to direct
afternoon winter sun is good protection. Construct a simple
frame, as high as
the tree or shrub is tall, around small trees and shrubs.
Simply pound four
wooden stakes (2” X 2” wood is adequate) around
the shrub or tree before
freeze-up. At freeze-up secure sheets of burlap, or other
fabric, to the posts
making sure the material does not touch the trunk or branches.
The aim is to
stop winter sunlight from ‘burning’ the foliage
and bark - not provide insulation
or complete wind protection to the tree or shrub.
Is there a Guarantee?
I hope with this information each of your plants survive
and reach maturity.
Unfortunately, in the horticultural world, it is impossible
to guarantee every
plant will survive and perform as stated in promotional
literature - even if there
is a written guarantee offered by the vendor. Knowledgeable
that gardening success equates to putting the right plant
in the right place and
that requires an understanding of purchased plants’ soil,
moisture and light
requirements and then carrying out proper planting and
until the roots are established.
No one said gardening was goof-proof or a ‘no
See fabulous gardens and historic
sites in the
Niagara area with
Phil & Carole Reilly of
Reilly’s Country Gardens nursery.
Details at 613-832-2965 or see