|
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.
- The tree is preparing for winter
by translocating sugars (stored energy) made by the leaves to 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 suns 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. 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.
- 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, and they are struggling)
Koelreuteria paniculata - Golden raintree
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 the pine, spruce, fir trees is 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 the peak 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 trees have black or brown spots on their leaves 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 closeup of the cones and leaves is located
at the House of Flowers on Evans Avenue. 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 the
lake at Absarraca, October 8, 2004.
|
