Pro Tips for Proper Winter Watering in Denver

The Christmas season is upon us and the winter chill has set in. It is so tempting to retreat to our warm indoor spaces and hibernate with feel-good hallmark movies! With all the craziness that 2020 has brought, many of our normal routines have been completely disrupted including lawn, tree, and shrub care. Find out why winter watering is essential and how to give your plants and trees what they need to survive this Denver winter.

Advantages of Winter Watering

For starters, you may be wondering do my trees and shrubs really need to be watered during the winter months? Absolutely, winter watering can really be a lifesaver for your trees! Watering is part of our regular tree and shrub care routine during spring and summer to prevent drought, but many people don’t realize that watering during a plant’s dormant season is just as beneficial. Here’s why:

  • Root development occurs during dormancy and is especially active in newly planted trees and shrubs. 
  • Steady winter watering helps prevent dehydration and premature death in young plants and trees.
  • Although trees are dormant, they aren’t just sleeping all winter long, your trees are growing their root systems. 
  • They require added moisture to stay alive and thrive. 
  • Winter temperatures in Denver are notorious for fluctuating. 
  • During an unseasonably warm or dry winter, even hardy established trees need supplemental watering.

Understanding Denver’s Winter Climate

You may have dressed your trees up with outdoor lights, but what they really want this Christmas is more water! It all has to do with Denver’s unique and unpredictable winter climate. Drought is a regular occurrence along Denver’s Front Range and there is not always enough snow cover to provide ample moisture to the soil. 

Many residents assume that the occasional snowfall or freezing rain will more than cover the watering needs of their property. But don’t count on nature to provide enough water for your plants and trees this winter. Denver is naturally semi-arid and relies on irrigation to promote much of the beautiful trees that are part of its landscapes. Doing your part and committing to winter watering will help keep the Denver landscape looking amazing come spring. 

Show Your Trees Some Love

Proper watering is advantageous for all Denver trees and shrubs, but some species really need the extra boost:

Evergreen trees: these species benefit greatly from winter watering because they can lose water throughout the entire winter season. They keep their needles, but high winds can strip water from them, drying them out. Dryness results in brown, brittle needles that shed, and sometimes this can affect the entire tree. Winter watering will keep your evergreens lush and vibrant.

Deciduous trees: this beloved tree species are at great risk during the winter from dying. Their shallow root systems grow slowly throughout the winter and they often lose much-needed water through their twigs. Proper watering can prevent branch dieback and chlorosis that won’t show up until spring. 

With proper winter watering, you can give your trees every advantage this winter and reap the rewards come spring!

Winter Watering Pro Tips

We’ve established the necessity and importance of winter watering. Next, it’s all about proper execution. For example, how much and how often do I need to water? And, do I need any special watering tools? Never fear,  winter watering is simple and low-stress. Just follow these guidelines and tips from the Boulder Parks and Recreation Department:

How often do I need to water?

When considering a winter watering schedule, plan on watering your deciduous and evergreen trees up to two times a month between October and March. Always water during the day, when temperatures are above 40 degrees. This routine allows the water to soak in before freezing night temperatures. Do not water if the soil is frozen. 

Worried about water regulations? In Denver, hand watering, soaker hose, or drip applications are allowed up to two hours per area with no day or time restrictions.

How much water is needed?

To determine how much water is needed, do a quick check of soil moisture levels around the dripline of the tree. To accurately determine soil moisture, dig down at least 4-6 inches. 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 min. = Total Watering Time.

It’s all about finding the sweet spot and getting the right amount of water to the right location at your trees. The most important area to water for deciduous trees is within the dripline (from the trunk to the outer edges of the tree’s branches). For evergreens, water 3-5 feet beyond the dripline on all sides of the tree.

What basic tools and materials are needed?

Soaker hoses, soil needles, or hoses with a soft spray attachment can be used to water trees in the winter. Do not turn on your irrigation system to water your trees.

Mulch is a key material needed to help your trees and shrubs retain water throughout the winter. Pull mulch back from the tree trunk itself, and maintain mulch 4 inches deep around the base of trees and shrubs to hold in the moisture. 

Which Plants and Trees Should I Prioritize This Winter?

If you like to get outdoors for a hike in any season, then you know why Denver is known for having harsh, cold, and brittle winters. A side effect of this weather is the health of some plant and tree varieties can be put at risk due to drought injury. Of course, all trees, plants, and shrubs can benefit from winter watering and pruning but there are certain species that need extra care and attention. Here are a few recommendations for prioritizing your trees and shrubs with the highest need for attention:

  • Plants like European white and paper birches, Norway, silver, red, Rocky Mountain and hybrid maples, lindens, alders, hornbeams, dogwoods, willows, and mountain ashes all have shallow root systems. The dry periods during Denver winters put stress on these trees and their exposed root systems. This means these plants and trees need proper watering and extra attention. 
  • Many people assume that evergreens don’t need much care or supervision during the winter months, but this is actually untrue. Colorado State University suggests that Evergreen plants like spruce, fir, arborvitae, yew, Oregon grape-holly, boxwood, and Manhattan euonymus all need a regular winter watering routine to thrive. 
  • Perennials and woody plants are susceptible to the winter freezing and thawing because they often lack ground cover. This process opens cracks in the soil and the plant roots are vulnerable to the freezing cold. Extra mulch and watering can protect these plants. 

These particular plants deserve your careful watch and attention this winter. Reach out for a consultation with one of our expert arborists for more winter care strategies.

What About My Newly Planted Denver Tree?

Did you make some investments in your home landscaping while in quarantine this year? Many Denver residents took to sprucing u their property and it’s important to learn how to care for those newly planted trees and shrubs.

Newly planted trees are still trying to get established and are highly susceptible to winter drought injury. On average, it takes a year to establish each inch of trunk diameter for a young tree.  Your new trees are working hard to grow and need regular watering to keep up with the nutrients they are trying to produce. 

Here is what Colorado State University recommends for watering new-planted trees: 

  • Use sprinklers, deep-root fork or needle, soaker hose, or soft spray wand.
  • Apply water to many locations under the dripline and beyond if possible.
  • If using a deep-root fork or needle, insert no deeper than 8 inches into the soil.
  • As a general survival rule, apply 10 gallons of water for each diameter inch of the tree. For example, a two-inch diameter tree needs 20 gallons per watering. 
  • Use a ruler to measure your tree’s diameter at 6″ above ground level. 

Similar to newly planted trees, newly planted shrubs need significantly more water than established shrubs. This includes any shrub that has been planted for less than a year. However, during extremely dry winters all shrubs will benefit from watering from October through March. Mulching well around new shrubs at the onset of winter will also help them retain moisture and protect their root systems. 

Schedule a consultation with one of our certified arborists if you have concerns!