Watering Your Trees
Watering is a simple tool yet plays a crucial role in proper tree care that will help keep your landscape healthy and reduce some stress that may be affecting your trees. Trees need water in order to complete photosynthesis and transpire, which is essential for their survival. In the process of transpiration, water evaporates through the leaves causing water to be pulled up through the roots. This water carries nutrients, cools the leaves, and provides the necessary ingredients to carry out the process of photosynthesis. This cycle is constantly happening and if there is no water to be pulled from the ground it can cause the tree to become stressed as it can no longer carry out its normal functions.
The amount of water a tree needs depends on many factors, including the age and species of the tree, time of year, weather, and soil type. As a rule, newly planted and young trees require more frequent watering than older, well-established trees. But during extended periods of drought, all trees benefit from supplemental watering. Newly planted trees are still establishing their root systems. Check the soil around their roots often to see if it has dried out. For the first several months after planting, most of a tree’s roots are still within the original root ball, with some roots beginning to grow beyond this area.
The root ball and the surrounding soil should be kept evenly moist to encourage healthy root growth. If soil is completely dried out it can be damaging to a tree’s roots causing poor absorption to even root death; stopping the cycle and causing even bigger problems for the tree’s health. After a few months, expand the watering zone to cover the entire area under the canopy. It can take two or more growing seasons for a tree to become established, meaning the tree’s roots have ventured out of the original root ball it was planted in. It’s vital to provide supplemental moisture in those early years if nature doesn’t provide regular soaking rains. During hot, dry weather, new trees may require water as often as three times per week to ensure that the root ball doesn’t dry out. More mature trees tend to be able to survive off what water is provided; in most cases, they will have adapted to their environment. This being said you never want the soil to completely dry and in periods where there is a lack of rain watering is encouraged. It’s a common misconception that a tree’s roots are a mirror image of the aboveground canopy. In reality, an established tree’s roots usually extend well beyond the edge of the canopy, or drip line, so the area to water will increase with the size of the tree.
Watering should be completed either in the morning or in the evening when the temperature is cool. If watering occurs in the afternoon more than half of the water can evaporate before the tree has a chance to use it. What you are aiming for is moist soil. As mentioned previously, dry soil is not good but soggy soil is no better. Soil that is saturated for long periods of time can also have damaging effects on the roots. When watering, think low and slow. Watering too much too fast can again make the water unavailable to the tree. Watering too slow allows the water to percolate deep into the soil and encourages roots to grow down and out. You can use watering bags that hold a couple of gallons of water and slowly drip into the soil or turn your hose on low and set it around the tree moving it around the base occasionally. Adding mulch can keep water in the soil longer as well as fend off weeds and grasses that compete with water absorption. It is also important to consider the proper species for your location. Some trees will do better than others in more dry or wet conditions.