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It's
Time
To
Fertilize
Trees
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This past 8 months of weather has been particularly
rough on many of Wyobraska’s landscape trees.
Early October snowstorms stripped still green leaves
from not yet dormant trees and multiple spring
hailstorms have battered many of those same trees
around the region. Most trees will recover from
this double weather whammy, but you can help that
recovery by fertilizing trees over the next 3 to 4
weeks. In Wyobraska an annual fertilizing of
landscape trees is always important, but it will be
especially important to do so this year
What kind of fertilizer do trees need?
In western Nebraska and eastern Wyoming, trees
actually need two different kinds of fertilizer.
For ease of understanding, let’s call these two
different kinds of fertilizers major element
fertilizers and minor element fertilizers.
Major elements fertilizers are often the only
fertilizers used for trees, but in western Nebraska
and eastern Wyoming, it may actually be more
important to apply a minor element fertilizer to
your trees. This is because a tree that is
deficient in any of the minor elements cannot
effectively use the major soil elements that are
contained in the major element fertilizers. So if
you only have time to apply one type of fertilizer
to your trees, I recommend doing the minor element
fertilizing first.
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Previous Articles
Previous Articles
A
Loooooong Winter
March 10
Just Dirt
March 18
Horse Manure & Hot Air
March 25
Mulch
to do this Spring
April 01
Creating Long Term
Tree-lationships
April 15
Spring Blooming
Shrubs & Trees
April 22
New
and Improved
Nebraska Arbor Day
April 29
A
Normal Spring
May 6
The Winter of Eight Moons
May 13
Adding Style to your Landscape
May 20
Adding Style to you
Landscape Part 2
May 27
Summer School
June 3
Signature WyoBraska Plants
June 10
2009
Articles
2008 Articles
2007 Articles
2006 Articles |
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What is a major element fertilizer?
Major element fertilizers are the traditional
fertilizers similar to those that you use on your
lawn. They usually contain the elements
nitrogen, phosphorus, and potassium. The label
on the fertilizer product should tell how much of
each element is in the fertilizer product. This
information is usually contained in a three number
formula on the label. The first number is the
amount of nitrogen, the second number is the amount
of phosphorus, and the third number is the amount of
potassium. For trees, I recommend a fertilizer that
contains from 10% to 20% each of nitrogen and
phosphorus.
When
should I apply a major element fertilizer to my
trees?
Apply a major element fertilizer to your trees any
time during the months of June and July.
Fertilizing trees with a major element fertilizer in
early spring (before May 15), or in late summer
(after August 1), may actually do more harm than
good, so timing is important with a major element
fertilizer.
How much major element fertilizer should I use for
each tree, and how do I apply it?
A good rule of thumb is to fertilize all of the area
under the branches of a tree plus another 5 feet or
so. Use the following table to determine how much
major element fertilizer to apply to each tree.
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Trunk diameter measured 12" above ground, or
height of tree if evergreen |
Size of circle around tree in which to apply
fertilizer |
Amount
of major element fertilizer to apply |
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1” diameter |
6’ or less |
10’ diameter |
2 pounds |
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2-3” diameter |
7-8’ |
20’ diameter |
8 pounds |
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4-6” diameter |
9’-12’ |
30’ diameter |
12 pounds |
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7”+ diameter |
12’+ |
40’ diameter |
15 pounds |
The easiest way to apply the fertilizer is to spread
it like you do a lawn fertilizer, using either a
drop spreader or a “whirly-bird” fertilizer
spreader. If you have a nice, large circle of
mulch around your tree (8’ diameter circle or
larger) you may elect to simply spread about 2/3 of
the amount of fertilizer suggested above within that
mulch area, and water it in thoroughly.
What about minor element fertilizers?
When discussing fertilizers, the term “minor
elements” generally refers to the following chemical
elements which plants generally need in relatively
small quantities: sulfur, calcium, iron, zinc,magnesium,
manganese, copper, boron, molybdenum, and chlorine. But just because they
are needed only in small quantities does not mean
that plants can get along without them. The yellow
leaves and stunted growth of trees and shrubs that
are deficient in minor elements is a dramatic
illustration of the importance of these so-called
“minor elements”, and minor element deficiency is a
very common problem of trees and shrubs growing in
Wyobraska landscapes.
There are two easy ways to help your trees get the
minor elements that they need for healthy growth.
One way is to take out an 8’ diameter circle of
grass around the tree, then spread 5 pounds of
sulfur and two inches of a good compost over the
entire circle and very lightly work the sulfur and
compost into the top two or so inches of soil.
Finally place 3 inches of a wood chip mulch over the
top of the compost. The sulfur will help make the
minor elements in the existing soil more available
to your tree. Compost is rich in minor elements, so
the two inches of compost will be like a fertilizer,
and the mulch will help promote extensive root
growth, which will help your tree take in more minor
elements. |
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2008 Articles
2007 Articles
2006 Articles
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Another way is to use a fertilizer product that
contains minor elements. Most of these products
must be applied by digging or augering small holes
under the canopy of the tree and placing a certain
amount of fertilizer in each hole. Each product
will have specific directions, so take care to read
the directions before applying these products.
In
my experience, these are the two most effective ways
to “fertilize” your tree with minor elements. You
can perform minor element fertilization any time of
year because minor elements do not stimulate new
growth, they only allow for healthier growth.
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