The benefits of mulch are so
well known that the question no longer is “Should I mulch?” but “What mulch is
best for my landscape?” For die-hard gardeners, mulching is one garden task you
can do any time of year – even in the winter.
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| Gravel mulch at Kendrick Lake Gardens in Lakewood |
A mulch is any material that
provides protection and improves the soil when applied to the soil surface.
Mulches can:
- reduce surface evaporation;
- improve water penetration and air movement;
- control soil temperature fluctuations;
- protect shallow-rooted plants from freeze damage;
- improve soil structure and nutrient availability.
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| Small wood chip mulch around roses |
Your
first decision will be deciding between organic and inorganic mulch. According
to PlantTalk Colorado, the most common organic mulches in Colorado include wood chips,
chunk bark, pole peelings, pine needles, lawn clippings and straw. Organic
mulches gradually break down and add nutrients to the soil. Decomposition of
fresh wood mulches can create nitrogen deficiencies, so you’ll need to be
prepared to supplement the area with a fertilizer and replenish the mulch
occasionally
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| Gravel mulch at Kendrick Lake Gardens in Lakewood |
Inorganic
mulches are stone-based and include rock, cobblestone, pea gravel, lava rock
and crushed rock. They store and radiate heat, so avoid putting large areas of
unshaded rock next to your house.
Regardless which
type of mulch you choose, resist the urge to install plastic sheeting
underneath the mulch. Air and moisture don't penetrate plastic, so plant roots won’t
develop but weeds will still come through. If you need an additional weed
barrier, use an air- and water- permeable landscape fabric instead.
The selection
of a mulch depends on its intended use. If appearance is the main goal,
inorganic or inert mulches may be the best choice. If the main objective is
soil improvement, consider an organic mulch that gradually breaks down. If the
area is used primarily for annual flowers, it often is more practical to use a
temporary organic mulch, such as composted leaves or grass clippings that can
be turned under each fall.
Mulches used
to enhance appearance and control weeds may be applied at any time. Apply most
mulches to a depth of 3 to 4 inches. Straw, dried leaves and similar materials
can be applied to a depth of 4 to 6 inches. Around woody plants, push the mulch
away so it isn’t touching the woody bark.
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| Organic mulch from chipped Christmas trees |
On the next
warm winter day, take a stroll through your landscape and consider where you
can add mulch and take advantage of all its benefits.
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| Mulch can also be used for pathways |