The main symptom of a grade change is gradual decline and dieback. Dieback can occur quickly or take several years, depending on the severity of the root injury or altered root environment. At first only scattered dead branches are visible in the tree crown. These become more numerous each year until the tree finally dies. Other symptoms are poor growth, smaller than normal leaves and early fall color displays.

Little can be done to overcome the deleterious effects of grade changes. Whether a particular grade change will be injurious depends on the tree species involved and the type of fill. A few inches of clay fill is very harmful to oak, beech, or dogwood.
 
 

Lower the pH by applying sulfur. Use Table 1 as a guide for sulphur rates. You need to know the existing pH and the soil type to use the table properly.

Other materials, such as aluminum sulfate, are also used to reduce soil pH, but more of the alternative materials is needed to obtain the same change in pH.
 
 

Plants commonly affected by iron deficiency are pin oak, azalea, blueberry, rhododendron, and holly.

To treat plants, spray them with iron chelates. These are available from most nurseries and garden centers and provide a suitable solution for small plants. Spraying large trees is not practical.

Use trunk implants of soluble iron sources on trees. The plastic capsules are inserted into holes drilled in the trunks. As the trees grow, they cover the capsules. The disadvantage of this method is the necessity of drilling the holes in the tree trunk to make the implants.

Trees vary in their ability to tolerate repeated wounding. Drilling a series of holes in the trunk every two to three years may become a more serious problem than the deficiency. Keep trees with implants well watered and fertilized so they heal as quickly as possible.

Adding fertilizer that contains iron to a soil that is not sufficiently acid will not help. The plant roots will not absorb the additional iron until the soil is made more acid.
 
 

Applying manganese chelates or using trunk implants will suppress the symptoms. Branches sprayed in the spring with a manganese chelate will green up if manganese is the deficient nutrient.

Trunk implants will prevent the symptoms from occurring for more than one year. The tree should be kept healthy through fertilizing and watering so the implant wounds heal as quickly as possible. The disadvantage of this method is the need to drill holes in the trunk, as discussed under iron deficiency.
 
 

Soil, especially clay, becomes compacted when it is subjected to pressure, especially when the soil is wet. Such pressure can be caused by heavy construction equipment or repeated foot traffic. Avoid maintenance activities when the soil is wet, particularly if you must use heavy equipment.

Symptoms of compacted soil problems are similar to those caused by construction injury.
 
 

Clay soils drain poorly. That is, once clay soils are saturated, they retain moisture longer than other soil types. Plant roots growing in clay can be injured by excessive soil moisture during wet weather or by excessive irrigation.

Soil modification in the planting hole will not have long-term benefits. Water from the surrounding area will more easily enter modified soil, flooding the root system. Improving clay soils is difficult and usually not worth the effort.

Sandy soils drain very well but retain little moisture for plant growth. Adding organic matter will improve the water-holding capacity of sands for a while, but the organic matter will decompose over time and the soil will again hold less moisture. As with clay, it may be easier in the long run to select plants that will adapt to the growing conditions on the site rather than try to change them.

Drainage problems can be related to the grade or slope of the site. Both dry and wet situations can occur.

Plants on the top of a berm or slope may suffer from dryness. Water will soak into the soil at increasingly slower rates as the surface layer becomes saturated. If water is applied faster than the soil will absorb it, the excess runs off the hill and does not benefit the plant.

Wet spots occur in low areas where water collects from surrounding higher ground. A similar situation occurs when a tree or shrub has a planting well around it. If the surrounding lawn is watered too often, the water may run into the planting well and drown the plant.

Wet areas can occur where downspouts from the eaves trough empty. Often this is near the base of a plant, which is injured by the excessive amounts of water. Plants growing in mulches beds or planted in slight depressions will be most seriously affected. Such injury usually occurs only during prolonged wet weather or when the combination of irrigation and rain is too much for the plant.

Dry areas often occur near buildings, particularly under overhangs. Plants in these areas are often sheltered from the rain and so experience very dry soil.

Remove loose bark and broken branches as soon as possible after the strike. The tree may show no other effects or it may die suddenly within a short time. All you can do is to reduce other stresses, such as dryness and pests.
 
 

Shrubs that would collapse under heavy snow loads can be protected or supported. To protect small shrubs, place crates or wooden frames over them in the fall. The crate or the slats on the frame will support some of the snow load. Taller shrubs can be wrapped with cord. Tie the cord to the base of a stem and then wind it around the shrub. The tied bundle of stems will help support one another.
 

Cut back the stubs of broken branches to just outside the shoulder ring. Split trees can be put back together with a combination of threaded steel rods and cables, but the results may not justify the expense.

A large uprooted tree should be removed, but you may be able to save smaller trees. You need to replant the exposed roots as soon as possible. Sometimes the roots are not exposed but the root zone is lifted up when the tree's roots are pulled upward. In either case, guy the tree for support and then water to settle the soil back around the roots. Some dieback may occur. The extent will depend on the amount of root injury the tree suffered.
 
 

Plants affected by this type of injury often try to leaf out or even flower in the spring. Soon after the first hot weather occurs, however, they wilt and die. Often very little of the plant will try to leaf out. After the new shoots die, shrubs may send up new, more vigorous shoots from the base. These can be used to renew the plant. Trees will also try to grow, then die, but there may be no regrowth.

If the winter-injured plant is a named cultivar, it may have been budded or grafted onto a less desirable rootstock. New shoots on these plants may be coming from the rootstock. This is especially common on roses. A plant renewed from such shoots is often inferior to the cultivar, so it is best to replace it.
 
 

The crack occurs when the sun warms the trunk in winter, causing tissues to expand. When clouds or buildings block the sun or at sunset, the temperature of the trunk drops abruptly to that of the surrounding air and the trunk contracts. The outer part of the trunk cools and contracts faster than the inner tissues. This difference in contraction rates causes the outer trunk to crack from the inside to the outside.

Prevent frost cracks by wrapping young trees with paper tree wrap. The wrap should start at ground level and go all the way up to the first main branches. Fruit trees are sometimes painted with white latex paint, which reflects the sunlight and prevents the trunk's cracking.

Once a crack occurs, nothing can be done. Fertilizing a low vigor tree may speed up growth and close the crack more quickly. Frost cracks can allow rots or canker diseases to get established in the trunk.
 
 

Prevent the problem by shading susceptible plants. Use burlap screens, discarded Christmas trees, or any other simple shade source. Because injury usually occurs in late winter, you need not apply the protection until after Christmas.
 
 

Frosted flowers and new growth will be limp and turn brown. The browned and dead new growth of evergreens can remain on the plant until well into the summer. When noticed then, the frosted growth raises concerns about diseases when, in fact, the injury occurred many weeks before.
 
 

Plants that are regularly bent over by ice can be supported. Smaller plants can be supported with a bicycle tire inner tube looped loosely around the stems, but larger plants require cables. The supports need to be flexible--rigid supports may cause breakage at the point of support. Such breakage commonly occurs when wooden props or stepladders are placed under ice-laden branches.

Do not try to remove the ice. It normally melts in a short time. Ice-covered branches are heavy, so trying to remove ice is likely to cause additional damage.
 
 

Scorch can also be a symptom of insect and disease problems that interrupt the flow of water from the roots. Root diseases can reduce root efficiency so that less later reaches the leaves, which then scorch. If you can diagnose and stop the problem, you may be able to stop the scorching.

Scorching related to high temperatures may be due to lack of soil moisture or an inadequate root system. If dry soil is the cause, watering may stop the scorching. If the plant just does not have enough roots, it may scorch during very hot, windy weather even though soil moisture is adequate. Little can be done in this case.

Allowing the soil to dry excessively before watering can kill the roots. Then when the plant is watered, the reduced root system cannot supply enough water to the leaves.

Construction injury can cause compacted soil and root removal or death that leads to scorching.

Salt spray can drift to plants from nearby roads as the tires of passing cars kick up a salty spray. The water evaporates, leaving a salt residue. Short plants can be protected from the spray with tar-backed burlap screens. Larger plants cannot be protected. Road salt can also be a problem when salty runoff accumulates salt in the root zones of plants growing near the road.

Salt can injure landscape plants when salt used on porches and sidewalks is shoveled or swept onto nearby shrubs, where it accumulated on the foliage or in the root zones. Most chemical deicers will have the same injurious effects, though calcium chloride is not as harmful as sodium chloride. Fertilizer is sometimes used, but it, too, can build up to toxic levels. Sand and ashes are not toxic but have the disadvantage of being easily tracked into the house.

A third source of salt can be softened water running into septic systems. Evergreens will display browned foliage that forms a rough spiral as it moves up the tree. Trees may grow well for a number of years and then show symptoms when their roots finally reach the source of the salt.

Tree species vary in their susceptibility to salt injury. A susceptible species such as white pine should not be planted near roadsides where salt will be applied.
 
 

Repeated applications of repellents may be used to discourage stray animals.
 
 

The symptoms will vary with the type of pollutant and the severity of the exposure. Air pollution symptoms can mimic other problems, particularly nutrient deficiency, pests, water excess or deficiency, and temperature extremes. This can make diagnosis difficult.

If the suspected source of pollution is a single "point source," look for patterns of injury. The most severe injury should be downwind from the suspected source. Unlike pest problems, which normally concentrate on selected plant species, air pollution will injure many species in the area.

Chemical analysis of the leaves can detect fluorides or chlorides. Chronic exposure to sulfur dioxide can lead to a buildup of sulfur in the leaves. Acute short-term exposures may not cause a buildup, or the sulfur may be leached away by rainfall.
 

Occasionally other types of injury occur. Girdling can be a problem if dog chains are tied around a tree trunk. As the animal pulls the chain around the trunk, the chain wears the bark and girdles the tree. Horses, goats, and sheep will sometimes eat the bark from trees. Cats may use young tree trunks to sharpen their claws. Girdled plants usually die.
 
 

You can use repellents or cylinders of hardware cloth or sheet metal to protect the trunks and stems of trees and shrubs. The repellent or rodent guard needs to extend above the usual snow line so the animal cannot stand on the snow and feed above the protected area. Squirrels will clip off branches and gnaw the bark of trees. Squirrels clip the branches for use in nest building but drop many of them to the ground. The bark gnawing can leave small pieces of bark on the ground. Girdled branches will die.
 
 

A rather sudden yellowing affects the oldest set of needles on all the branches. The yellowing is uniform from the top to the bottom of the tree. The needles at the tips of the branches stay green. On a windy day, the yellowed needles blow off the tree and litter the ground. This is a normal process, so nothing needs to be done.

If the yellowing is not uniform, if it occurs earlier in the season or if the needles at the tips of the branches turn brown, the cause may be something other than natural fall needle drop.
 

Sycamore and silver maple trees tend to be most noticeable when shedding bark. Sycamore sheds bark in patches. When the bark drops off, the stem is bright green and then develops normal bark coloration. Silver maple sheds bark in strips, and the newly exposed bark is orange on healthy branches.

Bark shedding can be a sign of disease or some other problem. If the bark drops off and exposes bare wood, the shedding is a symptom of some type of problem. If the bark drops off and exposes new bark but not bare wood, the shedding is probably normal. Normal shedding can occur quite suddenly.
 
 

Perhaps the earliest symptom is a reduction in leaf size on the branches supplied by roots below the girdling root. These branches will develop fall color earlier than the rest of the tree. Eventually the branches die. If the tree has more than one girdling root, the entire tree may show symptoms.

A girdling root will affect the appearance of the tree trunk. Most trunks flare out or get wider where they enter the ground. A girdling root will prevent the flare. In some cases, the trunk will actually get narrower. A long, sunken area may occur in the trunk where the portion affected by the girdling root did not grow as well as the surrounding trunk.

When you suspect a girdling root, carefully remove the soil down to where the roots connect to the tree (generally 12 to 18 inches down). Inspect the trunk for girdling roots.

You can remove girdling roots, but the results may not always be desirable. Girdling roots are functioning roots, so removing them may kill branches not now affected. The presence of many girdling roots aggravates the problem. After removing girdling roots, fertilize the tree and water during dry weather.
 
 

If the plant is old enough, the growing conditions may be too poor to allow flowering. Plants that require full sun, for instance, may grow but fail to flower in the shade.

Cold winter temperatures may kill the flower buds. This often happens to forsythia, flowering dogwood, and peach. Nothing can be done to prevent this type of injury. Plants that are not fully hardy in Michigan will be most susceptible to cold injury.

Improper pruning may cause failure to flower. Some plants bloom only on last year's wood. Cutting the plants back severely removes all the flowering wood. This happens most often on climbing roses. Florist's hydrangeas carry flower buds at the branch tips through the winter. These are often pruned off in the spring.

Overfertilizing with nitrogen can sometimes cause plants to grow only leaves and stems. Such plants will be quite large but without flowers.
 
 

One of the most common explanations is lack of proper pollination. Some plants cannot pollinate themselves--they require a plant of the same species but of a different variety for cross-pollination. Two trees of the same variety will not pollinate each other--they must be different varieties.

Lack of pollination can occur if cold, rainy weather occurs when a plant is in full bloom. Such weather will keep bees from working, thus reducing or preventing pollination and fruit-set.

A frost while a plant is in flower will kill the flowers and prevent fruit-set.

Some plants are dioecious. This means all the flowers on a plant are either male or female. Both a male and a female plant must be present and cross-pollination must occur for the female to produce fruit. Examples of dioecious plants are holly, bittersweet, and yew.