In times of drought, when it hasn’t rained for a month or more, large, mature trees will need water to survive. And for at least two years after planting new trees, it should be watered every couple of weeks, and more frequently in dry weather.

For large mature trees, you should water them by soaking the ground in the drip zone of the canopy and not near the trunk. Turn a hose on and just run it don’t the ground and move it periodically.

Many homeowners believe that rain will suffice to keep their trees hydrated. When trees are young or the weather is dry, though, your watering can make a big difference in their health and survival. Let’s understand this process more deeply.

How To Water Mature Trees

When the top 6 to 9 inches of soil in the root zone are dry, it’s time to water a tree. Dig a small hole under the plant canopy using a spade or hand trowel and feel the dirt. No water is required if the soil is cool and moist 6 to 9 inches below the surface. It’s time to water if the soil is dry.

Wilting of leaves or branches

Temporary wilting is the first visible sign that trees and shrubs need to be watered.

Leaves wilt and droop during the day during transient wilting, but rebound at night and appear normal the next morning.

Wilting begins at the highest center of an established tree canopy and progresses downward. It is difficult to spot, especially in a mature, tall shade tree. However, monitoring soil dryness and watering when the top 6 to 9 inches of soil are dry is more effective.

  • During the dry season, water trees 2 to 3 times per week for the first few months, then every 3 to 4 days until the rainy season. During exceptionally dry, hot weather, it may be required to water more regularly.
  • When rain is scarce during the rainy season and the winter months, irrigate trees planted in late winter to early spring on a weekly basis. With the arrival of warm, dry weather, begin deep watering once or twice a week – water thoroughly.
  • Many trees will benefit from two or three deep soakings in the fourth or fifth year. Most established trees will benefit from heavy irrigation on a regular yet irregular basis, especially during the dry season. Keep an eye on your tree.

How much water to use

Under-watering and over-watering

One of the most difficult aspects of plant parenting is determining when and how much to water your plants. Because both overwatering and underwatering are equally damaging to your plants, finding a happy medium – the sweet spot – is crucial. Let’s look at some suggestions for achieving the ideal balance.

Tips if you are under-watering

If your plant is under-watered, give it a hearty drink of water, making care to get the water down to the roots, and consider cutting the time between watering in half. A decent rule of thumb is to examine the soil for moisture with your finger. Go ahead and water as soon as you sense it’s dry at least 2″ down.

Tips for over watering

Overwatering can cause trees and plants to drown due to a lack of oxygen in the soil, as well as root rot and fungus growth in wet soil. It can also be misunderstood as pest damage. When leaves are splashed with water too frequently, mold might form, so try to avoid getting leaves wet when watering.

If trees and shrubs suffer from under-watering, which stunts their growth and health, overwatering is wasteful and can be damaging to the health of trees and shrubs.

Over-watering causes water to enter pore spaces that would typically get occupied by oxygen. It may result in root suffocation and a deterioration in the health of the tree or shrub.

Watering plan

For established trees, a general rule of thumb is 10 gallons of water per inch of diameter. To measure, place a ruler at knee height or make your best guess.

When it comes to trees, the “how” is maybe the most crucial aspect of watering. Drip lines are the favored technique of irrigation because they are slow and deep (although spray from a garden hose will certainly work). In comparison to overhead watering or sprinkler systems, drip irrigation loses less water via evaporation.

Deep watering permits the root zone to absorb sufficient moisture. When installing a drip line, make sure it covers the full area beneath the tree’s canopy as well as a safe distance away.

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Measuring tree rooted spread

The root system of a tree grows in a spoke-like arrangement, with roots extending through the earth from a central point below the tree trunk. Knowing how far roots have spread is crucial for adequately watering trees. You can use a ruler or yardstick to determine the diameter of the trunk. Use a measuring tape to determine the circumference of the trunk.

Most tree roots spread 2-3 times the radius of the canopy, and often reach out 5 times the radius of the tree canopy or more in dry conditions.

So, for example, if a tree is 6m wide, the radius of the canopy is 3m.

The root spread = 2 (to 3) x canopy radius = 2 (to 3) x 3m = 6m (to 9m).

Therefore the roots will radiate out from the trunk to a distance of 6m to 9m, and up to 5 x 3m =15m.

Why mature trees need water

Water is necessary to strengthen their roots, and after growth begins, it functions as a carrier for mineral nutrients and food distribution.

Tree cells expand by increasing their volume, and in order to do so, they must absorb water. Furthermore, all metabolic processes require an aquatic environment to function. Water plays a lot of key roles in the plant’s physiology.

Photosynthesis and growth will halt as a result which results in the reduction of Plant yield. Therefore the use of irrigation water is intended to avoid this problem.

Methods of watering mature trees

Depending on where the tree got planted, the climate, and the amount of capital you are willing to invest there are several methods of watering trees.

Lawn irrigation

A lawn sprinkler system is an easy and effective approach to water mature trees that are planted in/near the lawn. Keep in mind that the turf and tree roots are both in the same rooting region and use the same water. The idea is to provide the lawn with enough water to compensate for evaporation. This is the amount of water utilized and lost by the plants due to evaporation.

Soaker hoses

Trees are an efficient way to water since they are porous and release water slowly, allowing for deep-root watering. Wrap a spiral of soaker hose around the tree and let it run for an hour or more, or as long as it takes for water to penetrate 6 to 10 inches. Applying one inch of water may take several hours. Depending on hose size and pressure.

Are deep root watering devices effective for mature trees?

Deep root watering devices are ineffective for irrigating trees since the bulk of tree roots are not located deep within the soil profile. Furthermore, the device must get moved around the tree frequently, which takes time. A sprinkler and a hose are better alternatives.

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What is the best tree-watering practice: lawn irrigation or soaker hoses?

Unfortunately, you can’t just sprinkle your trees while watering the yard because the water won’t get deep enough into the root ball.

The best choice is to use soaker hoses or drip irrigation, although an ordinary garden hose installed at the base of the tree would work. Overwatering might choke the tree’s roots, so be sure to move it frequently.

You can make a self-watering system without a hose by poking holes in the bottom of a 5-gallon bucket with little nails. Place the bucket near the tree and fill it with water. Water will slowly and steadily water your tree as it drains through the holes.

Can mulching prevent the soil from drying?

Mulching is an excellent technique to prevent soil from drying up too rapidly, especially in hot weather. Spreading a coating of mulch on the ground around plants to protect their roots is a long-established horticulture practice.

Can mulching prevent the soil from drying

Benefits of mulching

Mulches in home gardens change the temperature of the soil. A winter mulch, which is applied in the late fall, protects the roots, crowns, and stems of winter crops from freezing temperatures.

Mulch aids in soil temperature regulation. When temperatures rise, plant roots stay cooler. Mulch keeps the soil warm in the winter, protecting the roots from the cold.

How woody plants use water

Woody plants differ in their process of acquiring water, from soil from the non-woody plants. Studies have shown that woody plants can access substantial volumes of water from the pores and fractures of bedrock.


Transpiration is the process through which water moves from the roots to the atmosphere through the plant. The loss of water from the plant in the form of water vapor through the stomata pores (90 percent) and the cuticle drives transpiration (10 percent).

Transpiration loses nearly all of the water absorbed by the roots, and only a small fraction is utilized by the plant. Importantly, transpiration creates an energy gradient that regulates the ascent of sap through the plant, which is helpful since it cools the leaves and enhances mineral absorption.

According to research, at noon, the leaves of plants that are not water-stressed are around 4oC cooler than the surrounding air temperature. The plants use the evaporative cooling principle, which involves drawing heat energy from the plant to change the water molecule from a liquid to a vapor.

The tissue cools as a result of the heat loss. If the temperature rises too high or the flow of water from the roots falls short of that lost through the stomata. The plant will close the stomata and “shut down” in reaction to water stress.

The relative humidity of the surrounding air temperature and wind speed influence the rate of transpiration. If there is a breeze and the air is hot and dry then the transpiration rate is high.

Growth and development

Water is essential for the growth of trees as 80-90 percent of actively developing tissues are in leaves and root tips. It makes up about half of the woody parts of trees and plants (trunks, stems, and big roots.

Water goes along a plant’s xylem vessels, which act like capillaries and transport water to different regions of the plant. As water evaporates, it aids the plant in maintaining the right temperature. When water evaporates from the surface, the plant draws more water up through the roots to replenish it, which travels through the circulatory system of the plant.

Water plays an important role for the growth and development of trees.

  • 80-90 percent of actively growing tissue leaves are found here.
  • It makes up about half of the woody parts of trees and plants (trunks, stems, and roots).
  • Photosynthesis and other processes involved in plant growth, flowering, and seed generation are all fueled by this compound.
  • Aids in the fight against pests.
  • Transports minerals, nutrients, and other fluids throughout the plant.
  • Leaves, buds, blossoms, and new succulent stem tips gain firmness and form.

Organic mulches improve the conditions for plant growth by enriching the soil as they decompose. Organic matter-rich soils are easier to cultivate and produce greater results.


Water is also required to carry nutrients and carbohydrates from the soil to the plants. At some point, all plants will face water scarcity or drought. In rare situations, this can be lethal or drastically inhibit the growth of those plants. Understanding and analyzing what a tree needs is part of parenting it.

Planting and growing a tree benefits not only the environment, but all living things as well. The degradation of trees and forests is threatening the world’s variety. Many animal and plant species can be found in tropical forests. When forests are logged or burned, many of these species may become extinct.

Ben McInerney
Author: Ben McInerney - Ben is a qualified arborist with 15 plus years of industry experience in Arboriculture. He ran a successful tree service before turning to writing and publishing. Ben is dedicated to providing users with the most accurate up-to-date information on everything trees.