To begin with, evergreens
keep only one to four years of green growth toward the tips of
the branches. The number of years is dependent on weather
conditions, the health of the tree and the species. Needles
toward the trunk of the tree turn brown each year and drop off.
If weather conditions are just right, the needles all turn brown
at once. If there aren't any heavy rains or winds to help knock
needles off gradually, the brown needles are quite showy. They
will drop off and the appearance of the tree will return to
normal. The only exception is the green needles are now farther
away from the trunk.
Every evergreen has a "dead zone" for these reasons. A dead
zone has no green needles or buds in it. You end up with a dead
tree prune if you prune into the dead zone. This can also make
for unsightly trees when the branches become very long and begin
to droop. This exposes the dead zone and makes the trees appear
to be sparse.
Stressful years make the brown needle phenomenon more
pronounced. I would classify this year as highly stressful, with
the combination of heavy rains and heat. This type of weather is
worse on evergreens than most plants, because most evergreens
planted over the last 50 years really aren't very well suited
for central Illinois.
White pines are really a northern understory tree. That means
they are better suited for Wisconsin and north and in a mixed
timber with other trees that shade them. Spruces and firs are
mostly western, high-altitude trees. Red pines are native to the
Northeast and to northern Illinois, but they have some disease
problems. Austrian pines have many disease problems and don't
usually see 40 years old. The white (concolor) fir is another
western species but has held up about as well as any evergreen
in our area.
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As for what to do, just take good care of the trees. Fertilize
the lawn area around the trees at the lawn rate to supply a pound
each of nitrogen, phosphorus and potassium per 1,000 square feet in
the fall and the spring. The trees will get the fertilizer they need
before the grass can get it. The drying winds of winter may also
take their toll. Use a wind block, or treat with an anti-dessicant
such Wilt Pruf, to keep needles from drying in the winter.
Broadleaf weed control
Fall is a great time to try to control problem perennial weeds in
the lawn. The weeds are in the process of storing energy in the
roots and crowns so they can come out again next year. This
translocation of food also provides a great way to move pesticides
in the plants.
Problem perennial weeds would include things like ground ivy,
violets, speedwell and others. Of course, a treatment will also get
dandelions and plantain.
For most problem weeds, a combination of 2,4-D, MCPP and dicamba
will do the trick. There are many pre-mixed herbicides with these
ingredients. Many are adding triclopyr to the mixture as well, and
mainly for violet control.
Try to pick a day when winds are slight and when temperatures
aren't predicted to be above 85 degrees for a while. Normally the
late September time doesn't present the temperature problem, but
this year seems to be an exception. The dicamba can vapor drift
after application. Many gardens are about done, but flowers, shrubs
and trees are also translocating food. You need to be cautious
whenever applying chemicals. Read the label and follow all
University of Illinois Extension, Logan County]