Properly Watering Trees


Keeping trees healthy and irrigated properly in drought years is difficult. Drought makes growing healthy trees all the more challenging and reinforces the value of a majestic shade tree. Properly placed and maintained trees are an asset to the environment and to our community.

What a tree under “drought stress” looks like:
Ø Symptoms of drought injury to trees can be sudden or may take up to two years to be revealed. Drought injury symptoms on tree leaves include wilting, curling at the edges, and yellowing.

Deciduous leaves may develop scorch, brown outside edges or browning between veins.

Ø Evergreen needles may turn yellow, red or purple. They may also turn brown at the tips of the needles and browning may progress through the needle towards the twig.

Ø In continued drought, leaves may be smaller than normal, drop prematurely or remain attached to the tree even though brown.

Ø Often times, drought stress may not kill a tree outright, but set it up for more serious secondary insect and disease infestations in following years. For more information and pictures of drought symptoms, see:

Where to water your tree:
Deep watering to a depth of 12” inches below the soil surface is recommended.

Saturate the soil around the tree within the “dripline” (the outer edges of the tree’s branches) to disperse water down toward the roots.

For evergreens, water 3’-5’ beyond the dripline on all sides of the tree.

The objective is to water slowly, dispersing the flow of water to get the water deep down to the trees roots. Watering for short periods of time only encourages shallow rooting which can lead to more drought damage.

Don’t dig holes in the ground in an effort to water deeply. This dries out roots even more. A soil needle/deep root feeder attached to a hose is acceptable to insert into the ground if your soil is not too hard and compact.

Overhead spraying of tree leaves is inefficient and should be avoided during drought conditions. Watering at ground level to avoid throwing water in the air is more efficient.

Tree Watering: Amount of water needed and methods to use:

During the drought, trees must be given top watering priority over your lawn. However, caring for trees requires different watering methods than your lawn. During water restrictions, irrigation systems designed to water turf do not sufficiently water your trees. During the drought, trees should be given a higher priority than lawns. Lawns can be replaced in a matter of months whereas a 20 year old tree will take 20 years to replace.

How much water your tree should receive depends upon the tree size. A general rule of thumb is to use approximately 10 gallons of water per inch of trunk diameter for each watering. Measure trunk diameter at knee height. General formula: Tree Diameter x 5 minutes = Total Watering Time.

Example: When you hand water using a hose at medium pressure, it will take approximately 5 minutes to produce 10 gallons of water. If you have a 4” diameter tree, it should receive 40 gallons of water – multiply by 5 minutes to equal total watering time of 20 minutes.

All size trees should be watered April through September according to the guidelines below. All trees should also receive adequate water during the winter months too –For more information on winter watering, see below.

Water should be distributed evenly under the dripline of the tree.

The best watering method depends upon whether you have a small (1-7” diameter), medium (8-15” diameter) or large sized (16”+ diameter) tree.

Small Trees (1-7” diameter) –3 times per month, April through September.

Newly planted and smaller trees can get adequate water within the existing watering restrictions by hand watering with a soft spray hose attachment as a separate zone on your designated day.

¨ Small trees are best watered using the following methods:

Automated drip irrigation system/soaker hose.

End of the hose using a soft spray attachment at medium pressure

5-gallon bucket (with ¼” holes drilled in bottom) or watering bags – filled and set under the dripline.

Soil needle (deep root feeder) – Work the needle into the soil at an angle to a depth of 8 inches. Use the needle at low to moderate water pressure. Water the area under the branches in at least twelve sites. Scatter the sites around the area bordered by the drip line. For new trees and those planted within five years, place the needle at least three feet from the trunk. Water a minimum of four sites around young trees.

Medium Trees (8-15” diameter) -3 times per month, April through September.

Medium sized trees are best watered using the following methods:

Soaker hose coiled several times under the dripline of the tree.

End of the hose with a soft spray attachment to disperse the flow – use a medium pressure.

Soil needle (deep root feeder) – Work the needle into the soil at an angle to a depth of 8 inches. Use the needle at low to moderate water pressure. Water the area under the branches in at least twelve sites. Scatter the sites around the area bordered by the drip line. For new trees and those planted within five years, place the needle at least three feet from the trunk. Water a minimum of four sites around young trees.

Ø Large Trees (16”+ diameter) -3 times per month, April through September.
¨ Healthy mature trees should be able to withstand a short-term drought.

¨ Large trees are best watered using the following method:

End of the hose with a shower like hose attachment to disperse the flow – use a medium pressure.

Soil needle (deep root feeder) – Work the needle into the soil at an angle to a depth of 8 inches. Use the needle at low to moderate water pressure. Water the area under the branches in at least twelve sites. Scatter the sites around the area bordered by the drip line. For new trees and those planted within five years, place the needle at least three feet from the trunk. Water a minimum of four sites around young trees.

Additional Watering Tips…

Reuse the water you save waiting for the shower to warm up.

If you drain your kids’ pools, pour the water under a tree.

Redirect your rain gutters toward your trees.

Understanding tree roots

Most people do not understand what their trees’ root system looks like. Tree root systems consist of large perennial roots and smaller, short-lived, adsorbing roots. The large, woody tree roots and their primary branches increase in size and grow horizontally. At least 90% are located in the top 12” inches of the soil. Root functions include water and mineral conduction, food and water storage, and anchorage.

In contrast, adsorbing roots, although averaging only 1/16 inch in diameter, constitute the major portion of the root system’s surface area. These smaller roots grow outward and predominantly upward from the large roots near the soil surface, where minerals, water and oxygen are relatively abundant. The major function of adsorbing roots is the absorption of water and minerals.

Large roots and small adsorbing roots occupy a large area under ground. Typically, the root system of a tree extends outward well past the dripline, up to two to four times the height of the tree.

Listed below are tree maintenance procedures that can significantly increase a tree’s chance of making it through drought periods.

Ø Mulch around your trees with 4 inches of organic mulch to reduce moisture loss.

Use wood chips, shredded bark, leaves or evergreen needles as mulch – avoid the use of stone or rock near trees as this increases air temperatures and moisture loss from leaves and stems.

Pull back mulch 6” from the trunk of the tree.

Do not fertilize a tree that is under drought stress. Salts in fertilizer may burn roots when there is not sufficient water. Fertilizers may also stimulate top growth resulting in too much leaf area on the plant for the root system to maintain during periods of limited soil moisture.

Keep your trees healthy and pest free. Postpone any construction activities planned near your tree to reduce impact to the trees’ roots. If your tree has any insect or disease problem that may be adding additional stress – treat them accordingly to reduce the overall stress to your trees.

Properly prune trees and shrubs during time of drought to improve structure, limb stability and to remove dead and weakened branches. Leaving broken, dead, insect-infested or diseased branches can further weaken a tree during drought and set the tree up for deadly secondary insect and disease problems.

Many tree species are harmed by herbicides used in the lawn. Trees already stressed by drought can be harmed by a heavy application of herbicide in the root zone.

Following these guidelines will help preserve our trees, the most valuable assets to our landscapes, and will also meet guidelines for water conservation during drought periods.

Prioritizing watering needs for different types of trees:

The first trees to consider watering are those that will be most vulnerable and affected by dry conditions.
Newly planted and young trees (1-7” diameter) are not yet established and have a limited root system. These trees generally need supplemental water even when we are not experiencing drought conditions. Generally it will take one full year per inch of trunk diameter to get established. Ex. It will take 3 years for a 3” caliper tree to establish itself.

Trees growing within a restricted root zone. Examples are trees adjacent to a driveway or house, growing within a landscape strip between your sidewalk and the street, growing in a median or traffic circle.

Trees that have recently received root injury due to construction work will need supplemental watering because the root system has been compromised.

Next to consider are the trees that are generally better equipped to withstand drought conditions.

In continued dry conditions even older trees will start to show symptoms of drought stress and will need supplemental water although less frequently than younger trees.

Established drought tolerant species may also need supplemental watering with continued drought.

Volunteer trees (self-seeded) or “weed” trees typically have extensive root systems and need less water.

The need to water your trees in the winter:
Even in years when drought is not a concern – winter watering is crucial, especially with evergreen trees! Well-timed fall and winter watering may allow a tree to survive on less water than a regime of plentiful water applications during the growing season. Tree roots continue to grow throughout the winter and need moisture to survive. Generally, water one to two times per month October through March on a warm day when the ground is not frozen. Use the same amount of water as during the summer months.

Preparing Your Trees for Spring and Summer

Preparing Your Trees for Spring and Summer Storms

When storm season approaches, many people take precautions for their vehicles, home, and food supply, but many people neglect the trees.

According to the Federal Emergency Management Agency (FEMA), a branch of the United States Department of Homeland Security, “three-fourths of the damage that trees incur during storms is predictable and preventable”.

What Happens to Trees During a Storm?

Often the reaction of a tree to the wind dynamics of a storm has a direct correlation with the distribution of leaves on the tree as well as individual branches. Because there is more territory to catch the gust, wind forces tend to be more strenuous where the foliage is the heaviest.

Light rain and even small amounts of hard rain are helpful and necessary. Several hours or days of constant rain can loosen the soil around the tree and add weight to the branches and leaves causing a weak resistance to wind.

The pounding on the leaves and branches by hail can cause damage to elements of the leaves, branches and the trunk.

Pruning Do’s and Don’ts

Proper pruning can do nothing but help the tree and its support system, while improper pruning can make your trees more vulnerable to the effects of the storm. Always prune the damaged or dead limbs, branches that cross or rub up against another branch, and branches that are scarcely attached at the trunk.

You want to reduce the area of resistance for the wind, but you must also remember that trees need leaves and branches for photosynthesis and protection. The ANSI A300 Pruning Standards (American National Standards Institute) recommends pruning no more than 25% of the foliage in a single growing season. Since restrained in the amount you should prune, it is perilous to be meticulous removing live branches and foliage from the entire tree including the outer third of the crown.

“Lion’s Tailing” is a common mistake that can be disastrous. By thinning an excessive amount of lower branches, giving the tree a lion’s tail shape, the tree becomes top-heavy and more capable of toppling over in heavy winds. It can also generate long-term problems such as sunburn of the trunk and reduce the tapering of the branches.

Cabling, Bracing and Propping Systems

If you notice a tree that seems ill-prepared for storm season, a propping system may be the solution. These man made devices are designed to support the weight of the tree or individual branches and create limits of mobility for the tree. Many larger trees can benefit from these techniques, but should only be considered when there is a reasonable assurance that it will reduce the risk of tree failure and all other options are insufficient.

Annually employ a tree care specialist to come and evaluate your trees professionally to ensure appropriate attention and repair to your trees.

Needed Care and Maintenance for Fall Trees

The gardening season isn’t over once fall arrives, especially when it comes to trees. Fall is an excellent time for planting most trees. Many fruits and nuts are ripening now. It’s also important to do your fall tree care now to prepare them for winter.

Most trees can be planted in fall. The temperatures are cooler, stressing the trees less and allowing them a better chance to get their roots established. It also helps that by this time in the growing season, some places discount their plant stock.

Special Care For Young Trees
Young trees are especially susceptible to the temperature changes that come with winter in cold climates. They are usually not developed enough to withstand the constant freezing and thawing that may occur.

One way to help combat this is with a thick (3-6″)mulch layer. Do not put it right up against the trunk – this can cause moisture buildup that attracts fungus. You can use bark chips or leaves. Put this mulch layer down once the ground has frozen.

Another way is to wrap the trunk with burlap or tree wrap up to the lowest branch. This will also help protect the tree from salt spray from roads.

Watering Trees in Autumn
At the beginning of autumn, stop watering until the leaves fall from the trees. Once they fall, water your trees until the ground freezes so they will have enough water to live through the winter drought.

Watch for signs that your trees need fertilization. Some signs that may indicate a nutrient problem are:

Reduced growth in branches and leaves.
Yellow or pale green leaves (in those trees that do not turn yellow in fall).
Leaves changing colors and falling earlier than usual.

Fertilizing in fall can cause rapid new growth, which could be damaged in winter. Consider fertilizing in spring if possible.

Make sure to remove the 3 D’s – dead, diseased or damaged. They all serve as points where diseases or pests could enter. Removing them will also make the tree look better. You can also prune branches that aren’t growing the way you would like.

Do thin rather than shear on flowering trees – prune lightly because next year’s flower buds have already been formed, and heavy pruning would affect the next spring’s flower production.

Fruits and Nuts to HarvestFruits:

Citrus fruits
Figs in California

Black walnuts
Hickory nuts

Summer Tree Care

Summer Tree Care

Proper summer tree care can be a life and death issue for certain trees so, it’s important to know something about your trees’ needs.

    To Prune or Not to Prune

Regular pruning is not always necessary every year. Pruning can cause stress to a tree when pruning during hotter temperatures, or by pruning too much off a tree. Trees grow and produce leaves to manufacture sugars for fuel, and transevaporate water that keep them cool. Removing too many fuel producing leaves off a tree during the summer could cause it stress.

Too often pruning is done for the wrong reasons. If you prune a large tree to keep it small, perhaps you planted the wrong tree. Or it could be that you are over-watering and over-fertilizing, causing the tree to grow too big too fast.

Pruning during the summer deprives the tree of leaf area that it uses for shade as well as food production. Many trees have been thinned and pruned to the point that they provide no shade-even to themselves. Excessive pruning such as that exposes the tree’s bark to intense sun, and can be harmful to the tree. The tree is likely to get sunscald on the bark, especially on thinner bark trees or younger trees. This excessive heating of bark can lead to a condition which can cause limb death or total tree death.

Try to reduce summer pruning to the removal of only dead or broken branches, especially if they are over hanging a structure or walkway.

    Temperature – Hot Enough for You?

Heat is also a summer issue for trees. Decomposed granite used as mulch under or around trees absorbs and then reflects the heat and sun. This makes the radiant heat even more intense. Block walls, glass, structures, and water surfaces all reflect and/or absorb heat, and can affect nearby trees.

    How About a Little Water? I’m Parched!

The warmer months are an important time to provide water to the tree roots. Insure that your trees have enough moisture stored in their leaves, branches, trunks, and roots to sustain them during the summer. This is when they are growing and expanding, and transpiration is occurring. Otherwise, trees can be thrown into stress which could compromise the health of the tree.

In order for trees to have enough water, don’t wait until the tree is dying to water it. Infrequent but deep watering of the entire root system out to the dripline of the branches will benefit the tree the most.

During the summer, the trees may need to be watered every seven days or so. For smaller, newly planted trees a drip system with one or two emitters at the edge of the rootball would provide adequate irrigation. Turn the system on for about thirty minutes every two or three days. Watering needs should be reevaluated after the tree has been in the ground for a few months.


Another important consideration is how trees are staked and tied. It is not always necessary to stake and tie newly planted trees. If it is necessary (to keep the tree from falling over), do so with the idea that as soon as possible stakes and ties should be removed. Usually, the ties can be removed after one full growing season.

Keep your tree as vigorous as possible with good cultural practices. This can prolong the life of your tree, and allow you to bask in its shade and beauty all summer long.

Call today for a complimentary consultation from Arbor Care’s certified arborist and fully trained professionals for a summer tree care evaluation.

How to Properly Trim Living Tree Branches

The first step to properly trim a living tree branch is to try and identify the branch collar. A branch collar is built up stem tissue that can be found at the underside of the base of a tree branch. It is important that when you prune a branch that you do not damage the branch collar.

The correct method to cut a branch is to begin the cut just outside the branch bark ridge. When making the cut, you should position the angle of your cutting tool down and away from the stem of the tree to avoid damaging either the branch bark ridge or the branch collar.

Try to cut the branch as close as possible to the stem, but outside the branch bark ridge, so that stem tissue is not injured and the wound can seal in the shortest time possible. Cuts that are made too far from the stem sometimes form a tree wound that heals more slowly, increasing the chances for tree diseases.

You can assess the quality of your pruning cuts by examining pruning wounds after one growing season. A concentric ring of woundwood forms from proper pruning cuts. Cuts that are too far inside the branch bark ridge or branch collar result in pronounced development of woundwood.

Make sure to use sharp tools tools when you trim smaller branches. When you trim a smaller branch, the tool should be sharp enough to cut the branches cleanly without tearing the bark or interior matter.

When trimming branches that are large enough to require the use of a saw, you should support the with one hand or by tying it off while it is being cut. Some branches may be large enough to require multiple cuts for safety reasons and to ensure that the branch doesn’t break or crack under weight while it is being trimmed.

What is a Prefessional Arborist?

When you have a leaky faucet, you call a plumber. When you have an electrical issue, you call an electrician. In the same way, when your tree, shrubs or lawn need cared for, the person you should consult is a professional arborist.

An arborist is a tree and plant specialist. Arborists are trained in the development and care of trees and plants and is very knowledgeable about trees and understands how to properly care for them.

In the same way that hiring a plumber to fix a plumbing issue makes sense, hiring an arborist to care for your trees and lawn can ensure that your investment in the trees and plants surrounding your home or business is protected. Proper tree care is an investment that can lead to substantial cost savings. Well-cared-for trees are attractive and can add considerable value to your property.

Additionally, poorly maintained trees can create safety issues and become a liability. And pruning or removing larger trees can be very hazardous work. Tree work should be done only by those trained and equipped to work safely in trees.

To protect your investment in the trees and plants around your home, we invite you to contact Arbor Care. We send a licensed professional arborist to every service call to ensure all your tree and plant care needs are completely understood and a sensible care and maintenance program is developed.