Part 1:

Having a few trees in your yard is more than just a great way to beautify your landscape.  Trees also provide shade which helps keep your yard cool, so your lawn, plants and flowers need less watering.

Trees are frequently overlooked when planning an irrigation system.  It is a common misconception that tree roots will naturally “grow towards water.” On the contrary, tree roots do not grow through dry soil.  They require proper watering that encourages roots to grow deep and spread out to provide a sturdy base for the tree.

Here are a few irrigation tips to help keep your trees healthy and vibrant:

1. In general, trees should be watered enough to penetrate the soil to a depth of at least 18 inches. The type of tree and the season will determine your watering schedule.  Check with a professional landscaper if you're unsure how much water the trees in your landscape require.
2. Proper watering of new trees is very important, especially during the first year after planting. New trees require more water at the base than established trees, since new trees have not yet spread their roots out into the surrounding soil.  If you have just planted a new tree, you should completely soak the root ball and the area beneath the canopy when you water.  Make a basin by mounding up a ring of dirt around the tree to help direct water towards the root ball.
3. Unlike newly planted grass, trees should be watered for longer periods of time, but the watering should occur less frequently.   The longer soaking will reach deeper into the soil which encourages a deeper, drought-resistant root zone. 
4. It is important to remember that too much water can kill a tree as easily as too little water.  Overwatering prevents tree roots from getting the oxygen they need to stay healthy.  Make sure the root area is moist, but do not let the tree stand in water for more than a couple of hours before it soaks in.  If you have heavy clay soil, mix some coarse compost into the soil, or raise the area to improve drainage.
5. For established and mature trees, proper irrigation continues to be important.  As a tree matures, you should stop watering directly onto the base of the tree and expand the watering zone out around the tree.   One way to effectively meet a tree’s watering needs is to use drip irrigation around the tree reaching out as far as the canopy.   By expanding the irrigation in a loop around the tree, you will be encouraging the tree to develop an expansive and healthy root system.   

Part 2:

Our last issue gave some tips and techniques for proper tree watering.  But sometimes your trees need to thrive in difficult conditions where traditional watering doesn’t quite work. Read on to learn about an innovative irrigation solution that will keep those trees healthy and vibrant…

There are areas where it can be difficult to provide trees and shrubs with an adequate amount of water, even with the most efficient drip irrigation system.  Dry climates with heavily compacted soil, street medians and large planters can make it difficult get water down to the root zone using traditional irrigation methods.  Without proper watering, a tree might be unable to establish the strong root zone it needs to stay healthy and upright in extreme conditions. 

Rain Bird has developed an innovative Root Watering System (RWS) that delivers water below ground directly to the roots of the tree, helping to maintain a strong and healthy root structure.   A 36-inch long perforated mesh tube (which can be cut to a desired length) allows vital water, air and nutrients to bypass compacted soil and directly reach tree root systems.  An added benefit is that it provides excellent aeration which helps release trapped gases that may increase plant stress. 

The RWS connects to an automatic irrigation system, allowing you to regulate the amount of water your tree receives.  Water from a built-in bubbler or drip emitter fills the system, then thousands of tiny openings in the tube deliver water directly where the tree needs it, deep within its root system.  
 

When using an irrigation timer or controller that has multiple programs, place your trees on their own individual program.  This allows you to water on the tree’s watering cycle (usually every seven to fourteen days for established trees), rather than the general lawn schedule that can be multiple times each week.   Check with a landscape professional to determine the proper watering cycle for your tree based its species and your specific landscape conditions.