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Questions?
E-Mail
Forestry Division
If
possible, take a couple of digital photos of your tree or shrub
and include them with your questions. One photo should be a close
up of the problem area. The second photo should be of the entire
tree if possible.
Prepare
Your Trees For Winter
• Do not prune your tree
until all leaves have fallen off of the tree.
- The "no prune" time frame is variable, but usually
begins late-August to early-September through mid to late October.
- The tree is preparing for winter by translocating sugars (stored
energy) made by the leaves to the branches, the trunk, and
to the roots.
- Active tree root growth occurs in late summer and into fall.
As long as the soil is warm enough, above 45° F, the roots
will continue to grow.
• Water and Aerate the root zone around the
tree.
- Use a deep root water attachment on your garden hose. Click
here for deep root watering information.
- Soil should be damp for deciduous trees and moist (wetter
than damp) for evergreen trees. Although evergreens
are not actively growing in the colder months, water is still
lost through the leaves. In Wyoming, with dry and windy
winter months, providing water to evergreens is critical.
Depending on precipitation frequency and amount, evergreens
should be watered adequately at least twice a month, more
often if it has been warm, dry, and/or windy.
Avoid watering trees, especially evergreens, prior to windy
days.
- Lawn grass roots compete with tree roots for water, and the
grass usually wins.
- Be careful not to overwater. Soil needs to be porous, containing
small spaces between soil particles. These spaces are filled
with air and water. If the spaces are completely filled with water
or compacted, then air is excluded. Roots provide water and nutrients
for the tree. They need air (oxygen), water, and nutrients for
themselves to grow.
• Provide a ground mulch underneath the tree.
- Mulch can be any porous ground cover: wood chips, bark pieces,
porous landscape cloth, and rocks.
- Keep all mulches at least 3 to 6 inches away from the base of
the tree trunk.
- Limit the depth of mulches to 3 to 4 inches.
- Do not use fine materials such as grass clippings or saw dust.
The fine materials can hamper water and air movement into
the soil. They can also cause the loss of nitrogen in the
soil to due to a high decomposition rate.
- Mulch acts as a temperature buffer, and helps in soil water
retention.
• Provide shade to the trunk of young deciduous
trees. Except
aspen trees.
- Our high altitude with less filtering of the sun's rays through
the atmosphere, the lower winter sun to the south, and our abundance of
sunny winter days can cause heating on the trunks of trees, causing
some cells to become somewhat active (deacclimated to cold). At
night when the temperature can drop well below freezing, the heated
trunk cells will freeze and burst. This damage of the bark on
the south and southwest side of tree trunks is called sunscald,
frost cracks, or southwest disease. Young thin barked trees should
have the trunks shaded on the south and southwest side or
they can be wrapped using the tree trunk wrap found in garden
Centers. If you are using the paper tree trunk wrap begin wrapping
at the bottom of the tree trunk, overlap the wrap and keep it
tight going up to the lowest branches on the tree. Use electrical
tape to secure the top end of the wrap, the bottom portion of
the wrap, and in the middle of the wrapped trunk. To properly
secure the electrical tape, go around the trunk a few times so
the electrical tape is adhering to the electrical tape. The trunks should
be shaded or wrapped from mid-October through mid-April. Be sure
to remove tree trunk wrap each growing season or the tree trunk
may be damaged. All maple trees including boxelder maple and Canada
red cherry (chokecherry) trees are very susceptible to sunscald
damage. These two tree species will need to be wrapped each year
for several years.
- Spraying an anti-desiccant on smaller evergreens is a good option
to reduce the damage caused by winter sunlight and dry winds.
Check with a garden center for an anti-desiccant spray.
Watering Trees Year-round:
Avoid
watering near the tree trunk, especially on conifer trees (spruce,
fir, pine, and juniper), when high winds are expected
Minimum Water Amounts:
Apply 10 gallons of water for every
one inch of trunk diameter -- three-inch trunk diameter = 30 gallons
of water. Ten-inch trunk diameter = 100 gallons of water.
Check
Soil Moisture: Dig
down in the soil to a depth of 4 to 6 inches at the dripline of
the tree. Squeeze a clump of soil in your hand from that depth.
If the soil holds together in a ball or it leaves moisture on
your hand, then the soil is wet enough and no watering is needed.
Or, if you can easily push a screwdriver into the soil to a depth
of 6 to 8 inches, then the soil is probably wet enough.
Minimum
Watering Frequency: Consistent
temperatures above 80° F, Windy conditions -- Check soil moisture,
may need to water once every 5 to 7 days. Lower temperatures,
less wind -- Check soil moisture, water once every 7 to 10 days.
Evergreens such as pines, spruce, fir, and junipers require watering
year-round. All tree roots require damp to moist soil to survive
the winter.
Dry, windy
conditions in winter require evergreen watering at least once
to twice a month. On a warm day, with temperatures in the 40's
or higher for most of the day, apply water to the ground surface
around the tree. A deep root watering needle can also be
used, although it may be difficult to get the needle into the ground.
A face full of water can be expected if using a deep root watering
needle without a splash guard.
Watering
Method:
Best --Deep-root watering
needle that will attach to your garden hose. Water to a depth
of 6 to 8 inches.
Good --Surface watering in soil with good aeration, allowing
the water to soak into the soil to a depth of 6 to 8 inches. If
the tree exists in a lawn area the grass will get first use of
any surface watering. A lawn can be replaced in one year. It takes
a lifetime to replace a tree.
Watering
Zones for Larger Trees
The
center of the drawing above depicts the trunk of the tree. The
donut shaped area around the trunk of the tree depicted with the
dots shows the critical watering zone. The donut shaped zone extends
from inside the tree canopy dripline to the outside of the dripline.
Apply
water or allow water to soak into the soil in the watering zone
to a depth of
6 - 8 inches. Water inside the dripline half way to the
trunk. Water outside the drip line the same distance as inside.
Cut back on watering trees in late
summer to early fall. The temperatures are cooler and the deciduous
trees are moving into a dormant state or are in a dormant state,
so less water is needed. While the top part of the tree is showing
winter dormancy, the root system is very actively growing. The
peak time during the year for root growth is in late summer to
early fall. The roots will continue to grow as long as the soil
temperature is above 45°F. A wood chip mulch 3 to 4 inches
thick on the soil above the root system of a tree will maintain
a higher soil temperature for a longer period of time, allowing
continued root growth. If the winter is dry, provide water to
your trees, shrubs, and lawn. Water trees and shrubs at least
once a month during dry winters. Water during the daytime when
temperatures are above freezing and will remain there for most
of the day and into the evening. Conifers and other broadleaf
plants that are evergreen, meaning they don't lose their leaves
or needles during the winter, may require more frequent watering.
Although evergreens are not actively growing during winter they
still use water to maintain life functions. Apply water to the
trees in the root zone.
A large mature tree can have a root system that
will radiate out from the trunk more than 1.5 times the height
of the tree. A large 90 foot tall cottonwood can have roots 135
feet or more from the trunk. Tree roots in Cheyenne are mostly
in the top 2 feet of soil. The feeder roots, small fibrous roots
with root hairs, are the roots that take in most of the water
and minerals needed by the tree. Feeder roots are mostly located
in the top 12 inches of soil. Most feeder roots for trees are
just below the soil surface.
Drought years diminish ground water supplies.
Trees and shrubs, with their roots deeper than grass roots, depend
on an adequate supply of ground water. To provide adequate water
to a tree or shrub, a watering needle should be used to apply
water in the feeder root zone of the tree or shrub. A watering
needle, a hollow metal tube with holes in the tip, can be attached
to a garden hose. The process of using the watering needle, called
deep root watering, also aerates the soil allowing oxygen infiltration,
which is required for root growth.
To deep-root water a woody plant, begin at the
dripline of the crown. The crown dripline is the outer edge of
the extent of branch and leaf growth in respect to the ground
(See diagram above). Poke the watering needle into the ground
about 4 to 10 inches deep, allowing 18 to 24 inches between holes.
Leave the soil needle in the ground long enough to allow a gallon
of water to be applied. Determine how long it takes to fill a
gallon container with water, use the time determined, for applying
water in each needle insertion hole. To apply water and adequately
cover the fibrous root zone of the tree, apply water in a donut
shaped ring around the tree extending half way from the trunk
and beyond the dripline about the same distance. See the drawing
above. A watering schedule for a tree or shrub is infrequently
for a long duration, as opposed to a watering schedule for
a lawn, which is frequently for a short duration.
For example: Ideally, for a mature
tree with a crown spread of 30 feet or a 15 foot radius from
the trunk, begin the inner circle of the donut shaped ring at
8 feet from the tree trunk. The outer circle of the donut shaped
ring would be 22 feet from the tree trunk. The area within this
donut shaped watering zone would be 1319 square feet. To apply
1 inch of water to the surface of this donut shaped area, around
800 gallons of water would be used. By applying one gallon of
water in every soil needle insertion hole, every 2 feet apart,
around 650 holes would be made, and about 650 gallons of water
applied. The root system of the tree would get "first chance"
at water applied by the deep root watering technique. Each soil
insertion hole provides an entryway for air and therefore oxygen
can reach the tree roots. Since the deep root watering holes will
remain for awhile allowing water infiltration into the tree's
root zone, surface watering for a few months after deep root watering
should be sufficient. Another option would be to aerate the area
underneath a tree canopy using a grass aerating machine, which
would also allow water to soak into the tree root zone. The lawn
aerator pulls soil plugs out to a depth of 1 to 2 inches with
fairly close spacing. The lawn aerator used in combination with
fewer, approximately 100 deep root watering needle insertions,
should allow sufficient water into the root zone in this example.
Clay soils, common around Cheyenne can retain large amounts of
water for a long period of time. Be careful not to over-water.
Check soil moisture content by digging a small
hole to a depth of 4 to 6 inches. Get some soil at this depth,
squeeze it in your fist. If it makes a solid ball and doesn't
fall apart after bouncing it in your hand then the soil is wet
enough. If the soil ball feels gritty then it probably contains
sand and may not stay together after bouncing. If it has a sand
content and the soil ball leaves a moist residue on your hand
then it is wet enough.
Fertilizer can be applied using deep-root watering
holes. Do not fertilize during drought conditions. A soil
test is the best way to determine fertilizer needs. Contact the
University of Wyoming Laramie County Cooperative Extension Office
in Cheyenne at 633-4383 for information on doing a soil test.
Determine the amount of fertilizer required for the tree according
to the label on the fertilizer container. Apply the recommended
amount of fertilizer divided equally among the deep-root watering
holes or every other hole. Obviously this can be very tedious
work with this number of holes, but most yards have hardscape
(i.e. sidewalks, driveways, patios, or a street) overlaying the
donut shaped watering zone, thereby decreasing the number of holes
required. If a hardscape is present, place watering needle holes
closer together along the hardscape feature to get water to those
roots existing beneath.
Fertilize in the spring through early summer.
Stop fertilizer applications by late July. Fertilizer applications
during late summer and early fall can stimulate new growth, which
may not harden off enough when freezing temperatures arrive, killing
the new growth portion. Fertilizer can again be applied to the
root zone after leaf drop in the fall. Use low amounts of Nitrogen
(N), 8% or less. Make sure the fertilizer contains chelated Iron
(Fe) and Manganese (Mn).
Modify
your landscape to use less water with Xeriscape™:
Properly prepare the soil and install plants that
require less water to grow and thrive. There is a word for this
type of landscape, it is Xeriscape, pronounced zear·i·skap
(short i, long a in skap). "Xeriscape is a systematic concept
for saving water in landscaped areas" Xeriscape is
a registered trademark of Denver Water, Denver, CO and is used
here with permission.
Links: Xeriscape.org.
PlantTalk Colorado .
Seven fundamentals of Xeriscape: (directly
from Xeriscape.org)
• PLANNING AND DESIGN… for water conservation
and beauty from the start.
• CREATE PRACTICAL TURF
AREAS… of manageable sizes, shapes, and appropriate grasses.
• SELECT LOW WATER REQUIRING
PLANTS... and group plants of similar water needs together.
Then experiment to determine how much
and how often to water the plants.
• USE SOIL AMENDMENTS… like
compost or manure as needed by the site and the type of plants
used.
• USE MULCHES… such as woodchips,
to reduce evaporation & to keep the soil cool.
• IRRIGATE EFFICIENTLY…
with properly designed systems (including hose-end equipment)
and by applying the right amount of water at
the right time.
• MAINTAIN THE LANDSCAPE
PROPERLY… by mowing, weeding, pruning and fertilizing properly.
Xeric
Tree List:
Use the following link to see a list of xeric trees. The list
has been developed by Colorado State University Denver County
Cooperative Extension Master Gardener
program.
CSU/Denver
County Cooperative Extension Master Gardener
Denver has
a more moderate climate than Cheyenne. Therefore, several of the
trees on the Denver County Cooperative Extension Website list
will not grow well
in Cheyenne.
Trees that will not do well in Cheyenne are:
Chilopsis linearis - Desert willow
Catalpa ovata - Chinese catalpa
Catalpa speciosa - Western catalpa (there are three in
Cheyenne that I am aware of, two are struggling and one looks
great!)
Koelreuteria paniculata - Golden raintree (one tree in
Cheyenne that I am aware of, it was in full bloom 8-7-08)
Quercus imbricaria - Shingle/Laurel oak
Quercus robur - English oak
Quercus robur 'Fastigata' - Columnar English oak
Quercus undulata - Wavy leaf oak
Several other trees on the list will be hard to
find. Check with a tree nursery or garden center on availability
of the trees.
The CSU/Denver County Cooperative Extension Master Gardener
Website has many great ideas and suggestions for planning, installing
and maintaining a Xeriscape. This link is the main Xeriscape page.
Master
Gardener - Xeriscape
Xeriscape is not zeroscape. Zeroscape is similar
to a parking lot of asphalt, concrete, or packed soil, where nothing
grows. Water runs off of a zeroscape, which wastes water and causes
flooding. Plastic rolled out onto the ground with rocks placed
on top is not Xeriscape.
Is foliage on your
conifers turning yellow or brown this fall?
Ponderosa
pine (top two photos) and blue spruce with brown and/or yellow
needles on the interior part of the trees.
Autumn brings a beautiful array of
leaf color on deciduous trees, shrubs, and vines. Coniferous evergreen
trees such as pine, spruce, and fir have leaves in the shape of
needles. In the fall the needles in the interior part of the tree
will turn color or fade and fall off of the tree. Conifers, cone
bearing trees, most of them are evergreen, can have many years
of needles on the branches. As the tree grows the interior needles
become shaded and no longer contribute to the manufacture of food
for the branch and tree. Leaves and limbs die when they become
more of an energy sink rather than an energy producer for the
tree. Drought conditions cause a water shortage for woody plants
contributing to more needle and limb die-back than normal. Yellowing
needles on the interior limbs of pines, spruces, and firs are
normal during the fall season. Extensive yellowing on interior
needles seen on some trees is compounded by the drought conditions.
Yellowing needles on the outer tips of main branches can indicate
another problem.
It is important that all woody
plants, especially pines, spruces, firs, and junipers are watered
in the winter. If the upcoming winter has little snow fall,
pick a warm day and water around the dripline of evergreen trees
at least once a month and possibly twice a month. Woody plant
roots need to be kept moist throughout the winter even though
all trees are in a semi-dormant state. Dry winter winds can cause
water loss through the leaves on evergreens to the point of causing
significant limb die-back or entire tree mortality.
During September or October, use a
deep root watering needle that will attach to the garden hose
and water all around the dripline of the tree. The
dripline is the circle formed by the outer extent of the branches.
Water from the dripline circle half way to the tree trunk and
the same distance outside of the dripline circle. Poke the deep
root watering needle into the ground to a depth no more than eight
inches. Allow a half gallon to one gallon to be dispensed into
each hole or until the water runs out of the hole. Move the deep
root watering tool 18 to 24 inches away and repeat the watering
amount. The deep root watering holes will remain for some time,
allowing above ground sprinkling or surface watering to soak into
the holes directly benefiting the tree's root zone.
Autumn is a good time for woody
plant root growth. The leaves are finished making food for
the season and the food is being translocated and stored in limbs,
trunks, and roots. A two to three inch deep mulch layer of rough
material like wood chips or bark pieces spread over a tree's root
system helps the soil retain moisture, moderates the temperature
of the soil, reduces surface plant competition with the woody
plant roots, and reduces the need to use lawn equipment next to
the trunk of the tree. Warm soil temperatures combined with moist
soil enhances root growth well beyond the time when leaves have
fallen off of deciduous trees. Roots need air spaces in the soil
to get oxygen for root growth and they need water. Soil saturated
with water, and compacted soil eliminates air space in the soil
and will reduce or eliminate root growth.
Did
your aspen or apple tree leaves have black or brown spots in midsummer
?
Aspen and some of the apple varieties
had various leaf spot fungus on their leaves this past summer.
Trees with leaf fungus problems are best treated when the leaves
are not on the trees. In the fall after leaf drop, thoroughly
rake up and throw away the leaves. Overwintering leaves
are a source of infection the following spring. If your trees
have leaf fungus problems every year, spraying with a fungicide
in the spring as the leaves are emerging from the buds and one
or two more times during the summer, will reduce the leaf fungus
problems.
Fall Color in Cheyenne
(All photos taken by Cheyenne Urban
Forestry Division)
Autumn
Purple Ash in the center and a Green
Ash on the right, September 28, 2006
The Autumn Purple ash is a cultivar of white ash
(Fraxinus americana). The Green Ash (Fraxinus pennsylvanica)
is a common urban forest tree. The leaves turn yellow in the fall.
Autumn Purple Ash
- outer leaves are dark purple to bronze in color, while the inner
leaves are yellow. Photo taken September 29, 2006.
 
Larch
or Tamarack tree showing fall
colors on November 3, 2004.
The tree above and the close-up of the cones and
leaves is located at the northeast corner of Evans Avenue and
East 23rd Street. The tree is a larch or tamarack tree, a deciduous
conifer, and is not native to Wyoming. The larch is in the
pine family, but the leaves (feathery groups of fine textured
needles) turn yellow and fall off of the tree every fall. "Deciduous"
means the tree leaves come off of the tree in the winter to save
on water loss in temperate climate trees. "Conifer"
means a cone bearing tree. Cone structures are where the tree's
seeds develop. There are native conifer species of pine, spruce,
fir, and juniper in Wyoming. Another deciduous conifer,
nonnative to Wyoming, is baldcypress.
 
Autumn
Blaze Maple - October 7, 2004.
Red
oak
leaves in Lions Park, October 7, 2004.
American elm
in Lions Park, October 10, 2004.
Virginia creeper
also known as Woodbine (red leaves) climbing into a tree at Lake
Absarraca, October 8, 2004.
Cottonwood
and willow trees lining Lake
Absarraca, October 8, 2004.
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