A Colorado Specific Watering Guide by CreekSide Tree Nursery

How often should I water my tree?

The best way to think about watering your tree is to break it down to the simplest details first and then build off them as you get more comfortable. There are two factors and two primary watering seasons. The first factor is frequency and the second factor is volume. The frequency is how often you need to water your tree. The volume is the amount of water you need to apply to the tree at each watering event.

Watering Frequency is how often you water.

The frequency is determined by they type of tree, the location or exposure in the yard, and the time of year. The most common and easiest way to determine the frequency is to look at the time of year. During the time when deciduous or leafy trees have their leaves is season one. This is typically spring, summer, and some of fall. During this time you will need to provide irrigation approximately every other day until plants are fully established. The second season is the time when deciduous trees have lost their leaves. This is considered “Winter Watering”. Winter watering is often overlooked but is very important to your trees health. During this time you will adjust your frequency to once per week or twice per month depending on the weather and tree type.

Watering Volume is the amount you put on the tree each time you water.

Now that you understand frequency let’s look at how to calculate the volume of water to put on the tree. We recommend starting with a simple calculation. At each irrigation, apply 2 to 3 gallons of water per inch trunk diameter (e.g. 4 to 6 gallons for a 2-inch tree) over the root ball only.

When is my tree establish so I can stop watering?

It could take three to five years to full establish a new tree. While every situation is different we feel that once your tree is established you can water twice per month in warm weather in spring, summer, and fall and once a week in winter. Do this for at least an additional three to five years.  After this, most trees should be able to survive on natural rainfall with a few supplemental waterings during each season, However keep an eye on your investment.

A newly planted shrub can die in a matter of hours in the hot sun if it does not have proper watering.

These watering schedules typically work for spring, summer, and fall. However, as the summer sun beats down and temperature rise, you may have to increase your watering…especially if you start to see yellow or “crispy” leaves. Because there is much involved in watering a newly planted tree, we’ve listed a few things to keep in mind as you begin to establish this tree in its new home: Yours. You will not always have to hand water your tree or turn on its drip irrigation system. However, keep in mind that the first two years of your plant’s “new life” in your yard will need to be monitored. After two years, and if the tree received proper care, the tree/shrub should have enough roots developed to pull the water it needs from the ground and/or from your sprinkler system’s runoff. Now keep in mind that additional watering is encouraged during the hot and dry period’s throughout your plants life. For an established plant, watering once a month should be a good place to start. Some trees will require more water than others and still others will require significantly less than the recommended amounts above. This will all depend of the variety of tree chosen. When determining a watering schedule, start by looking at your soil. When the tree was planted, was the soil moist or dry? Determine the reason for the moisture or lack there of. If your soil is naturally moist, or your water table is high, you may not have to water your tree as often as your neighbor might. However, the reverse may apply as well. It’s important to note that in Colorado, while we do get some heavy downpours and some wet snows, we do not get enough of either element to correctly water your newly planted tree or shrub.

Just because it rained the week before does not mean you should skip your watering schedule for the current week.

(Ask yourself if you need a drink after just walking out your back door. The same conditions that fatigue us as humans also affect the plants. Remember this when you see your plant just sitting outside day and night without anything to drink.) Water is the key ingredient to a healthy and happy plant. You can use all the root stimulators, fertilizers, and specials composts you can buy, but they are only addons and can never replace the value of water. All roots on transplanted trees are located in the root ball so delivering water on top of the root ball is most efficient.

What does all this water talk mean?

Keep your tree(s) and/or shrub(s) moist. The soil around the tree and the soil located about 18” beneath the root-ball should have the consistency of play-dough. You should be able to ball the soil into your hand without dust being left behind or water squishing out. You do not want dry dirt around your tree, nor do you want mud. It’s the happy medium between the two that should be your goal. On the flip side, it is important to remember that your tree/shrub cannot possibly stay this “moist” forever. Life happens. The soil beneath your tree may dry a bit. This will not kill your plant if it happens occasionally. Ironically, while trees need adequate water to grow, they also need oxygen in order to promote root growth. The roots of your tree will actually begin to spread during these “drier” times, which is why it is impossible for your tree or shrub to stay moist incessantly—the roots are using the water! If trees receive irrigation during establishment and then regularly during the life of the tree, or if you are planting in the plant’s native range and soil type, any tree regardless of drought tolerance can be planted.

Watering your new plants properly is the most important thing you can do.

In addition to exposure irrigation capabilities at the planting site should be considered before selecting trees or shrubs for a planting site. There are many ways to water a tree, however we tend to promote a few ways that produce the best results.

1. For most situations we tend to water simply, such as with a hose. Or, you can attach a bubbler to the hose and lay it at the base of the tree near the trunk.
2. We sell a product called a “Tree Gator”. This product can make water super easy. The “Tree Gator” can really help with the winter watering.
3. If you have the means for a drip irrigation system, by all means use it. Just remember that you still need to pay attention to the tree and make sure that the system is working adequately. We have seen a lot of trees suffer or die simply because their emitter was clogged.

You should also consider the rate at which you water your new plants. Slower is always better. Example: If you take a bucket of water, fill it up, and then dump it out onto the ground, the water will soak in minimally and give you a pretty wide wet spot. Now, if you take that same bucket of water, cut a few small holes in the bottom, fill it up, and then let it slowly drip out over several hours, the water will soak in deeply and the wet spot won’t be quite as wide. If you were to dig down in both instances, you would find that the wet spot from the first bucket would only be wet a couple of inches down in the ground. The second bucket, which dripped the same amount of water but over a long period of time, would be soaked 4-5 times deeper than the first bucket.

Irrigation management after planting

Irrigation is imperative to a trees overall health and survival.

Regular irrigation after planting encourages rapid root growth that is essential for tree establishment. Irrigation helps maintain and encourage the desirable dominant leader in the tree canopy on large-maturing trees. Instead of a dominant leader, trees that are under-irrigated during the establishment period often develop undesirable, low, co-dominant stems and double leaders that can split from the tree later.

Splits (so-called frost cracks or sunscald) along the lower trunk have also been associated with under-irrigation after planting. Since most root growth occurs in the summer months, irrigation during this time is crucial. You could loose almost an entire year’s root growth if you under-irrigate the first summer.

Should I use a Deep Root Watering Wand/Stake?

We usually reply that the wand is meant for plants with partially or fully established root systems. This is because, most of the time, the wand is used incorrectly and is either obstructive to the roots, or placed in the wrong position. The problem with the wand is usually the depth and the pressure. The wand may sometimes be placed too deep and the pressure too high. This digs holes in the loosened soil under your plants causing them to sink. Also, by applying the water below the roots, the water misses most of the plants “small” root system and basically wastes that water. This can be very inefficient.

I have a sprinkler in my yard. Will that work to water my newly-planted tree?

Unfortunately, the answer is NO. It can definitely help keep the tree cool in the summer and help add to the water it receives from you during its scheduled watering, but it cannot and must not replace the water you would have given it had the sprinkler system not been there. If you are to rely on the sprinkler system as the sole provider of water for your trees, you must know that you are promoting surface roots. A shallow rooted tree is a bad tree. Instead, deep-root water your tree, by allowing the water to saturate the ground beneath the tree. Again, use a simple hose or drip-irrigation system. Do not rely on your lawn sprinklers to water your trees—trees need directed water to reach the roots.