ORNAMENTALS
Water Landscape Plants Before Winter
This has been a dry fall for much of Kansas. Watering now is
important if soils are dry to help alleviate moisture stress.
A good, deep watering with moisture reaching at least a foot down
into the soil is much better than several light sprinklings that just
wet the top portions of the soil. A deep watering will help ensure that
the majority of roots have access to water. Regardless of the watering
method used, soil should be wet at least 12 inches deep. Use a metal
rod, wooden dowel, electric fence post or something similar to check
depth. Dry soil is much harder to push through than wet.
Although all perennial plants benefit from moist soils before
winter, it is especially important for newly planted trees and shrubs
due to limited root systems. Even trees and shrubs planted within the
last 2 to 3 years are more sensitive to drought than a well-established
plant. Evergreens are also more at risk because moisture is lost from
the foliage.
Trees or shrubs planted within the last year can be watered
inexpensively with a 5-gallon bucket. Drill a small hole (1/8″) in the
side of the bucket near the bottom. Fill the bucket and let the water
dribble out slowly next to the tree. Refill the bucket once more, and
you have applied 10 gallons. Very large transplanted trees and trees
that were transplanted two to three years ago will require more water.
A perforated soaker hose is a good way to water a newly established
bed or foundation plantings. However, soaker hoses are notorious for
non-uniform watering. In other words, you often receive too much water
from one part of the hose and not enough from another. Hooking both the
beginning and the end of the soaker hose to a Y-adapter helps equalize
the pressure and
therefore provide a more uniform watering. The specific parts you need
are shown in the photo
above and include the soaker hose, Y-adapter and female to female
connector. It is also helpful if
the Y-adapter has shut off valves so the volume of flow can be
controlled. Too high a flow rate
can allow water to run off rather than soak in.
On larger trees, the soaker hose can circle the trunk at a distance
within the dripline of the tree but at least ½ the distance to the
dripline. The dripline of the tree is outermost reach of the
branches. On smaller trees, you may circle the tree several times so
that only soil which has tree
roots will be watered.
If using a soaker hose, note the time watering was started. Check
frequently to determine the amount of time it takes for water to reach
12 inches. From then on, you can water “by the clock.” Use a kitchen
oven timer so you remember to move the hose or shut off the faucet. If
you are seeing surface runoff, reduce the flow, or build a berm with at
least a 4-foot diameter around the base of the tree to allow the water
to percolate down through the soil, instead of spreading out. (Ward Upham)
FLOWERS
Winterizing Roses
Though most shrub roses are hardy in Kansas, other types of roses
can be more tender. For example, the hybrid teas have certain species in
their ancestry that originated in the warm climate of southern China.
These roses need protection to reliably survive Kansas winters. Mound
soil or compost about 8 to 10 inches high around each plant. If using
soil, bring it in from another part of the garden. Do not pull it from
between plants because this can damage the rose roots or make them more
susceptible to cold.
Mounding is normally finished by Thanksgiving. After the ground has
frozen, add a 4-inch mulch of straw, leaves or hay for further
protection. More soil may be spread on top of the mulch to keep it in
place. Do not add the mulch before the ground freezes or mice may invade
and feed on the roses over the winter. The purpose of these coverings is
not only to moderate the cold, but also to prevent warm days during the
winter or early spring from stimulating growth that is tender to
returning cold weather. Excessively tall canes should be pruned to a
height of 36 inches and tied together to prevent them from being whipped
by strong winter winds. Wind can damage the crown of the plant or loosen
the surrounding soil.
Next spring, remove coverings before new growth starts. If soil was
used for mounding, remove from the area so that the level of soil stays
constant from year to year. Wait until after the ground thaws, or the
tops may begin growing before the roots can provide water. (Ward Upham)
MISCELLANEOUS
Winterizing Roses
Though most shrub roses are hardy in Kansas, other types of roses
can be more tender. For example, the hybrid teas have certain species in
their ancestry that originated in the warm climate of southern China.
These roses need protection to reliably survive Kansas winters. Mound
soil or compost about 8 to 10 inches high around each plant. If using
soil, bring it in from another part of the garden. Do not pull it from
between plants because this can damage the rose roots or make them more
susceptible to cold.
Mounding is normally finished by Thanksgiving. After the ground has
frozen, add a 4-inch mulch of straw, leaves or hay for further
protection. More soil may be spread on top of the mulch to keep it in
place. Do not add the mulch before the ground freezes or mice may invade
and feed on the roses over the winter. The purpose of these coverings is
not only to moderate the cold, but also to prevent warm days during the
winter or early spring from stimulating growth that is tender to
returning cold weather. Excessively tall canes should be pruned to a
height of 36 inches and tied together to prevent them from being whipped
by strong winter winds. Wind can damage the crown of the plant or loosen
the surrounding soil.
Next spring, remove coverings before new growth starts. If soil was
used for mounding, remove from the area so that the level of soil stays
constant from year to year. Wait until after the ground thaws, or the
tops may begin growing before the roots can provide water. (Ward Upham)
MISCELLANEOUS
Garden Soil Preparation — It’s Not Too Late
Autumn is an excellent time to add organic materials and till
garden soils. Winter can still be a good time to take care of this chore
as long as the soil isn’t frozen. It is far wiser to till now than to
wait until spring when cold, wet conditions can limit your ability to
work soils easily. Working soil when it is wet destroys soil structure
and results in hard clods that are very slow to break down. On the other
hand, dry soil may need to be watered so it can be more easily tilled.
Be sure to wait several days after watering to let soil moisture levels
moderate. You want the soil moist, not wet or dry, when tilling.
There is a limit to how much organic material such as leaves can be
added in one application. Normally, a layer 2 inches deep is adequate
with 5 to 6 inches being the maximum that can be added at one time.
Shredding the material before application encourages faster and more
complete decomposition due to increased surface area. Remember, soil
preparation is an important key to a successful garden. (Ward Upham)
High pH Soils and What to Do With Them
Though there are high pH soils in most parts of the state, alkaline
soils tend to be more common in the central and western regions of
Kansas. These high pH soils can cause problems for plants by reducing
the availability of certain micronutrients. For example, most Kansas
soils have more than adequate amounts of iron. However, a high pH can
make iron unavailable resulting in a condition known as iron chlorosis.
Iron chlorosis reduces the health of plants by reducing photosynthesis.
Lowering the pH of such soils will eliminate iron chlorosis.
Now would be a good time to have a soil test done to see if your pH
is too high. If so, sulfur can be added either now or in the spring to
lower the pH. Different textures of soil require different amounts. A
sandy soil needs 1.0 to 1.5 pounds of sulfur per 100 square feet to
reduce pH one point. A loam soil needs 1.5 – 2.0 pounds and clay needs
2.0 – 2.5 pounds to do the same. For example, if you wished to lower pH
from 7.5 to 6.5 on a loam soil, you would need 1.5 – 2.0 pounds of
sulfur per 100 square feet.
So, what pH do we shoot for? For most plants, a pH between 6.0 and
7.0 is preferred. Unfortunately, adding sulfur to lower pH is not as
clear-cut a solution as we would like. Here are some other factors to
keep in mind.
Free calcium carbonate: Some soils have free calcium carbonate,
actual particles of limestone mixed in the soil. These “calcareous”
soils normally have a pH of 7.3 to 8.5, with 8.2 to 8.3 being most
common. In order for us to lower the pH with sulfur, all free calcium
carbonate must be neutralized first. A recent soil test showed 6.7
percent free calcium carbonate. One pound of sulfur is needed to
neutralize three pounds of calcium carbonate. Assuming 80 pounds for a
cubic foot of soil, you would need about 1.75 pounds of sulfur per
square foot just to neutralize the free lime. Additional sulfur would be
needed to lower pH. Adding this much sulfur to a soil at one time is not
recommended.
Not all high pH soils are calcareous. Perform this simple test to
see if your soil contains appreciable amounts of free lime. Apply one
drop of vinegar to dry soil. A vigorous fizz usually means the soil
contains at least 3 percent calcium carbonate. A mild fizz suggests a
calcium carbonate of between 1 and 2 percent and a fizz that can only be
heard suggests the soil has a calcium carbonate content less than 1 percent.
How sulfur works: Elemental sulfur does not lower pH directly. It
must first be oxidized to the sulfate form with the result being
sulfuric acid. The sulfuric acid produces hydrogen, which acidifies the
soil and lowers pH. The oxidation takes place primarily through
microbial activity.
Oxidation takes time: Microbial oxidation of elemental sulfur takes
time and depends on:
– number of sulfur oxidizing bacteria present
– temperature (75-104 degrees optimum)
– moisture content of soil (too wet or too dry will slow down process)
– size of sulfur particles (the smaller the better)
A single sulfur application normally takes at least 2 years for
most the sulfur to react and form sulfuric acid. This, of course,
depends on the above factors. So, what do you do about calcareous soils?
See the companion article in this week’s newsletter for specific
recommendations. (Ward Upham)
Iron Chlorosis and Calcareous Soils
Iron chlorosis due to high pH soils is a significant problem in
Kansas. Though Kansas soils normally contain adequate amounts of iron,
a high pH makes that iron unavailable to the plant. Iron plays a major
role in the production of chlorophyll. Thus, a lack of iron reduces the
amount of chlorophyll and results in yellowing of leaves. Iron chlorosis
weakens, and in severe cases, may kill a susceptible plant.
A popular recommendation for high pH soils is adding sulfur to
lower pH. This works well for many soils, but not those that are
calcareous. Calcareous soils are those that contain actual particles of
calcium carbonate (limestone). Calcareous soils can be difficult to
practically impossible to acidify because the sulfur must neutralize all
the free limestone before the pH is affected long term. In many cases
you would need well over a pound of sulfur per square foot just to
neutralize the free lime.
So, what do you do? That depends on the situation. With vegetable
gardens and annual flowerbeds, work products into the soil during the
time of year when there are no plants present. Oregon State University
suggests mixing 5 pounds of sulfur per 100 square feet into the soil
before planting. The idea is to form little pockets of acidity that
result in enough iron availability for the plants during the year of
application. Note that this must be done each year. Another possibility
is to use iron chelates. Iron chelates hold the iron in such a way that
the plant can get to it. However, not all iron chelates will work in
high pH soils. For soils with a pH over 7.2, use a chelate that contains
FeEDDHA (Ethylene diamine-N,N bis(2hydroxyphenylacetic acid)). This can
be found in the products Sequestar 6% Iron Chelate WDG, Sequestrene 138
and Millers FerriPlus. Chelates can either be mixed into the soil at
planting or sprayed on the foliage early in the season. Reapply as
needed. (Ward Upham)
Why Do Houseplants Lose Leaves After Being Brought Inside?
Newly bought houseplants or those brought in from outside often
lose at least a portion of their leaves. In order to understand why this
occurs, we need to look at how these plants are grown and what the plant
needs to do to adapt to its new environment. Houseplants are normally
produced either under shade outdoors in southern states or in
greenhouses. Also, many homeowners move their houseplants outside during
the summer. Regardless, the plants receive much more sunlight than they
do in an indoor environment. Research done in Florida in the late 1970s
revealed that tropical plants grown under high light conditions produce
“sun leaves” while those grown under low light conditions have “shade
leaves.” These leaf types differ structurally in that sun leaves have
less chlorophyll (the substance that plants use to convert sunlight to
energy) and the chlorophyll that is present is located deeper inside the
leaf. Sun leaves also tend to be thick, small and numerous while shade
leaves are more thin, larger, and fewer in number. When plants are moved
from one light condition to another they need time to adjust. This
process is known as acclimatization. If they are forced to acclimatize
too quickly, they will drop their sun leaves and produce a new set of
shade leaves. If the acclimatization process is slower and less drastic,
the plant can convert their sun leaves to the shade leaves that do
better under low light. If going from shade to sun, this process is
reversed.
Some houseplants are acclimatized before they are sold but many are
not. So how do we help our new houseplants or those moved inside
acclimatize to their new home environment? Houseplants should start out
in an area of the home that receives plenty of light and then gradually
moved to their permanent, darker location. This process should take 4 to
8 weeks depending on the degree of difference in light levels between
the initial and final location of the plant. Remember, plants need to be
acclimatized whether they are moved from a sunny location to one that
receives less light or from shade to sun. Understanding plant processes
allows us to anticipate potential problems. Acclimatization gives our
houseplants a greater chance of retaining leaves and avoiding the
stress of completely replacing them. (Ward Upham)
