Common Lawn Weeds:
There's something soothing about seeing
an even expanse of green grass that seems to lower our
blood-pressure a bit. And to some people, when that expanse is broken up by
something growing where it shouldn't be growing, it seems to raise it a notch or
two. Weeds are just one type of plant that we have decided shouldn't be growing
in one particular place. Wild orchids growing in Hawaii are considered weeds
there. It's just your point of view as to what makes a weed a weed. Some
weed-type plants are very invasive and fast growing. Their growth habit
overtakes our cultivated turf plants, depriving them of food and water.
Some common lawn weeds are annuals.
Sprouting from seeds, they develop, blossom and form new seeds, then die in the
fall, repeating the process each year. Crabgrass is one such weed. The ideal
control prevents them from developing. Applying a Pre-emergent Control in the
spring does this. The soil's surface is covered with a microscopic protective
layer that prevents any germinating seeds from taking hold, including crabgrass.
If left undisturbed, this protective layer will maintain its defensive qualities
throughout the prime germinating period. This is when most weed seeds will
normally start developing. Additional seeds may be carried in by winds, birds,
or any number of other methods.
Clover was once considered an integral part of a
healthy lawn and was included in packaged lawn seeds. Clover is actually
a legume that affixes nitrogen to the soil which in turn is used by the
grass. It wasn't until the advent of broad-leaf weed killers after World
War II, that clover began to decline in acceptance by the homeowner,
thanks in part by the marketing efforts of the manufacturers of the weed
killers. Because clover is a broadleafed plant, you can't put down a
broadleaf weed killer to get rid of say dandelions and not kill the
Crabgrass is a warm season annual grass which grows
best in the heat of midsummer when desirable lawn grasses are often
semi-dormant and offer little or no competition. Crabgrass overwinters
as seed, comes up about mid-May or later, and is killed by the first
hard frost in fall.
Crabgrass grows best in full sun. It does not grow in shady places.
Crabgrass can be controlled in a number of ways, but the best defense
against crabgrass is a thick vigorously growing lawn that is mowed no
closer than 2 1/2 inches for cool season grasses.
Fertilize the lawn in late summer or fall and again in spring to develop
a dense, healthy stand of grass. Fertilized bluegrass does not go into
midsummer dormancy as soon as unfertilized bluegrass. Pre-emergent
applications made when soil temperature are still below 60 are the best
prevention. Not recommended for areas where new grass seed is going to
be planted during the first half of the growing season. Applications
lose their effectiveness if the lawn is raked or disturbed during the
first half of the growing season.
Postemergence crabgrass herbicides are now available. These are products
that are applied after the crabgrass seed has sprouted. The herbicide
(ACCLAIM) gives excellent crabgrass control with one application. This
product should be applied when crabgrass is in the 3 to 4 leaf stage of
Broadleaf weed. Best treated during active growing
cycle with a spot treatment. If you use a dry granular form of weed
killer or a weed and feed type of fertilizer, apply it to wet grass and
weeds. The weed control material must stick to the leaves of the weed
plants to be effective. If you spray a liquid, apply it only on a calm
day so material will not drift onto desirable plants.
Moss does not develop in healthy
lawns. Lack of fertility, soil compaction, poor drainage, shade and poor
soil aeration are the most common cause of moss in lawns. Moss is not
directly harmful to grass, but moves into bare spots in the lawn as the
grass thins out. Lime has often been suggested for moss control. Lime
will raise the soil pH but will do little or nothing to prevent moss
growth. The fact that the soil is acidic has little to do with the
growth of moss. In fact, we see moss growing on limestone and concrete.
If your lawn area is moist and shady, you will have difficulty
controlling moss because you have an ideal environment for moss growth.
Moss is often troublesome in spring when temperature are cool and soil
Mushrooms, also called toadstools or puffballs, are
fruiting bodies of soil fungi. They appear in lawns during wet weather
in spring and summer. Mushrooms live on organic matter such as roots,
stumps and boards in the soil. Most don't harm the lawn but are
unsightly. Mushrooms that grow in arcs or circles of dark green grass
are called fairy rings. The arcs or rings enlarge from 3 inches to 2
feet each season as the fungi grows outward. The fairy ring fungus may
interfere with water flow through the soil and stress the lawn.
There is no chemical control for mushrooms. Time is the best cure. Once
the buried wood has completely decayed the mushrooms will disappear.
Break mushrooms with a garden rake or lawn mower for temporary control.
This helps to dry the mushrooms and reduces the risk of children eating
them. Control individual mushrooms by removing the organic matter. Dig
up and remove the wood. Fill and reseed, or sod, as needed