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Mulch
Nature's
Winter
Blanket
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Actually snow is nature’s
winter blanket, but in a region that can’t always
count on a dependable snow cover, mulch is another
option to protect the roots of landscape plants from
cold, dry winter weather. Regular readers of this
column know that “Mulch” is one of my favorite
topics—for the simple reason that in 30 years of
working with plants in western Nebraska and eastern
Wyoming, I have seen nothing that improves the
health of landscape plants like mulch.
For newly planted trees, mulch
is literally the key to survival. The numbers are
overwhelmingly convincing. In my experience, over
80% of newly planted trees that aren’t mulched die
within three years of planting. Conversely, over
80% of newly planted trees that are mulched are
thriving after three years. One of the primary
benefits of mulch for newly planted trees is that it
keeps lawn mowers and string trimmers away from the
tender bark of young trees. Most of the difference
in rates of survival between mulch and un-mulched
newly planted trees is undoubtedly due to the
ability of mulch to keep the lawn mowers and string
trimmers away from the base of trees.
But mulch also provides a variety of additional
benefits including moisture retention, soil
temperature moderation, elimination of competition
from other plants like grass, and the development of
active soil ecosystems on which the root |
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A six foot diameter circle of
mulch around a young tree is the minimum size of
mulch area that will insure quick establishment and
healthy growth. An 8 foot diameter circle of mulch
is better. The mulch should be 4 inches thick.
Grass will grow rather quickly into this mulch area
through the spring and summer. Do not try to pull
this grass or trim it down with a string trimmer.
The easiest way to control grass in mulch is to use
round-up or a similar non-selective contact
herbicide. Spraying the encroaching grass two times
a season will normally provide good control. It’s
easy and fast.
Some mulch products are clearly
better than others. The best mulch, in my opinion
is shredded hardwood. It is widely available in
either bagged or bulk form. Its shredded texture
keeps it from blowing out of beds in even the
windiest of conditions. Its composition allows it
to break down at a moderate rate and develop a
healthy soil ecosystem. And its color gives the bed
a natural, soil-like color. The shredded hardwood
mulches are generally made from either the
byproducts of hardwood timbering operations or the
recycling of municipal tree debris. They generally
contain a mixture of leaf, bark, and wood tissues—an
ideal blend for feeding a soil ecosystem. |
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Previous Articles
It's
Finally Spring - March 13
Spring Garden Calendar-March 20
No
Garden Left Behind-March 27
Planting Trees for a Cooler Earth in a Warmer
WyoBraska-April 3
Viburnums - Shrubs for Wyobraska Springs-April 10
Want A Water Conserving Lawn? You might already have
one-
April 17
Creating Long
Term
Tree-lationships April 24
Bigger, Bolder, Brighter,
Better—and Back In The Landscape May 01 & 08
Hardy Shrub
Roses
May 15
Another Look
at Native Plants
May 22
No Child
Left Inside
May 29
June
is Tree Care Month June 05
Summer Blooming Shrubs
June 12
Roses Are
Red.....
June 19
The Plants They will be Talking About Next Year at
the Garden Walk
June 26
Busy Summertime Gardens
July 03
Cutting Your Lawn Down to Size
July 10
July 17
Insect Paranoia
If It Will Grow In Wyoming...
July 24
Rain Gardens
July31
WyoBraska Native Grass & Wildflower Lawn
August 7
A Real WyoBraska Peach?
(Fruit Trees) August 14
Fall is for Planting
August 21
A Recipe for Enjoying Autumn Landscapes August 28
Seeing Red in your Landscape
September 4
Four Questions to Ask A Plant
September 11
September Plants
September 18
2007 Articles
2006 Articles |
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systems of many trees depend—in
other words, mulch is the original slow release
fertilizer. For shrub and perennial beds, mulch
offers one additional benefit—weed control.
Properly applied and maintained mulch reduces 90% or
more of weed germination, making weed control a
minor maintenance task.
There is no single right time
to apply mulch. For a variety of reasons, spring
and fall tend to be the main “mulching seasons”.
Spring is often a good time to add mulch to
perennial beds, simply because that is the time,
right after cleaning up the old stems, when a new
layer of mulch can be placed over the entire bed
without having to work around any actively growing
plants. As a rule of thumb, March is the best time
to remulch perennial beds.
The major exception to this
rule is that tender or marginally hardy perennials
may need to receive some extra mulch in the late
fall to help their crowns survive the winter.
Hybrid tea roses and some hydrangeas fall into this
category. Mulching tea roses and tender
perennials should be done as late in the fall as
possible—generally late November.
Trees can be
mulched or remulched at any time of year. There is
certainly benefit to mulching an unmulched tree in
the fall. There is now clear evidence that if soil
temperatures remain warm enough, trees “feed”--or
pull nutrient elements out of the soil, all winter.
Mulch not only provides some of these nutrient
elements, but more importantly it can keep the soil
temperatures warm enough to allow root growth and
feeding activity to occur through much of our long
winter season. I am beginning to think that the
ability of mulch to enable winter feeding may be one
of the major reasons that mulch has such a profound
effect on the survival rates of newly planted trees
in Wyobraska. |
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Shredded redwood has become a
popular mulch in Wyobraska. It is a good mulch in
that it does not blow in windy conditions and it
maintains a nice reddish-brown color over time. It
lasts a long time—up to four years, which is both an
advantage and a disadvantage. While it does not
need to be replaced as often as other mulches, it
also does not do as good a job of developing a
healthy soil ecosystem—in other words, redwood mulch
is not as good a slow release fertilizer as shredded
hardwood mulch. Shredded redwood is only available
as a bulk product. A comparable mulch that is
available in bags is shredded cypress mulch.
Bagged and bulk shredded cedar
mulch is also widely sold. I do not recommend
shredded cedar mulch because it often contains a
high percentage of chips which blow around in even a
moderate wind. Like redwood, it is also slow to
break down, and thus is also poor at soil
development. Shredded cedar was one of the original
mulch products available, and it is well-entrenched
in many distribution channels, but the superior
performance of the now readily available shredded
hardwood products makes shredded cedar a product to
avoid, in my opinion.
Unfortunately, crushed rock and
river rock are also still widely used as “mulches”.
In my opinion, rock is never a mulch. While it can
be used as a groundcover in certain landscape
applications, it should never be used as or
considered a mulch. Crushed rock and river rock are
often sold as “low-maintenance” mulches, but nothing
could be farther from the truth. In a few years
the rock mulches almost always silt in with dirt and
weed seeds, making a maintenance mess that is
difficult to clean up. And rock mulches do nothing
to promote a healthy soil ecosystem—in fact the weed
barrier products often used with rock mulches
prevent any new organic matter from reaching the
soil, effectively starving the soil microorganisms
which are the basis of a healthy soil—and healthy
landscape plants.
With winter approaching, these
beautiful fall afternoons offer a good opportunity
to spread out some new winter blankets in your
landscape.
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