Early Spring Tree Care Tips To Set Up Yard Trees for a Healthy Growing Season in Denver

Spring officially begins in March in Denver, but we might be surprised by polar plunges and snowstorms in April. Trees go into full pitch, sending nutrients to their leaf and flower buds. The following spring tree care tips create a good foundation for healthy tree growth.

Spring Clean-Up Tip

The following clean-up tips will give trees a clean slate for a healthy growing season.

  1. Debris Clean-up – Removing yard refuse denies the opportunity for emerging insects to spread destructive fungi and bacteria to other sections of a tree or neighboring plants.
  2. Weeding and Mulching – Spring is a great time to weed since the ground is soft and weeds are easy to pull up. After weeding, remove all debris two to four feet away from the trunk and lay down mulch to retain water and prevent weed growth. The mulch should be three or four inches deep, and the wood chips should not touch the trunk.

Spring Watering Tip

Since most trees planted in Denver are not native, it makes sense that they will benefit from supplemental watering. Maintaining consistent soil moisture allows for better water absorption. Not watering makes trees more vulnerable to disease, insect infestations, and branch dieback. Tree roots are not like carrots; instead, they spread two to four times wider than the tree’s height, with most of the absorbing roots located in the top 12 inches of the soil. Since mature trees need about 10 gallons of water per inch of the trunk diameter, most homeowners do not have the time or equipment to water large trees. Ross Tree has the tools and trucks to water the largest trees in the Denver area.

Spring Pruning Tip

To keep a yard safe, any fallen or hanging branches need removal. Well-maintained trees avoid mechanical breakage caused by heavy snow. Early spring is ideal for pruning because fewer leaves make it easier to see the tree’s structure and its defects. Homeowners should call a tree service company like Ross Tree for safety and structural pruning. We have the equipment to reach high into tall trees. While on sight, our arborists will check for split or cracked bark, broken or hanging branches, winter kill, squirrel damage, and insect infestations. If we find harmful insects, Ross Tree will make a treatment recommendation. 

Proper tree pruning encourages growth, good structure and improves the aesthetic appeal of a tree. Pruning at the right time and in the right way also saves homeowners money. The best way to ensure proper tree trimming is to hire a tree company with International Society of Arboriculture Certified (ISA) Arborists on staff. Ross Tree’s three arborists adhere to ANSI Tree Pruning Standards when pruning trees. For more information, check out our Standards-Based Tree Pruning Handbook.

Spring Fertilization Tip

Early spring fertilization gives trees an extra boost of nutrients before they start growing and blossoming. Ross Tree recommends not using fertilizers with Nitrogen because yard trees get plenty of that element from grass fertilizers. We instead focus on giving tree Phosphorus, Potassium, and micro-nutrients. Plants use Phosphorous to help form new roots and grow seeds, fruit, and flowers, while Potassium is associated with the movement of water and nutrients in plant tissue. We add microbes and mycorrhizae to improve nutrient uptake. Spring fertilization allows trees to build up a food reservoir for the growing season.

Top Tree Insects to Look for This Spring

Ross Tree Company abides by our motto, Integrity in Action, which means residential and commercial property owners can expect the correct use of tree insect control products needed for the job. Ross Tree has three ISA Certified Arborists on staff to help identify tree pests and four Qualified Supervisors licensed by the Colorado Department of Agriculture to handle and apply pesticide products. Spring weather also triggers harmful tree insects’ mating and feeding cycles. Adults emerge from where they overwintered and mate. The females look for places to lay their eggs. After hatching, their larvae start to feed as trees leaf out. The Ross Tree Insect Calendar helps homeowners identify tree insects that might harm their trees. The calendar gives approximate times for treatment by insect species. Treatment timing varies depending on weather, temperature, location, and adult and egg emergence. Below are insects to watch out for this year.

  1. Evergreen Beetles

    Spring and summer spraying protect pine trees from Mountain Pine and Ips Beetles. There is no cure or treatment for these destructive pests, so preventive care is the best approach to protect high-value trees. For more information, check out our Pine Tree Care Handbook.

    MPB adult

  2. Elm Leaf Beetle

    Wet springs support the growth of Elm Leaf Beetles and other insects that attack Elms growing in Denver. Elm Leaf Beetles overwinter in the adult stage. When spring comes, the adults chew on the leaves and mate. After their eggs hatch, their dark grub-like larvae skeletonize leaves. In large outbreaks, these beetles cause damage and can even defoliate an entire Elm tree. For more information, check out our Elm Leaf Pest in Denver Handbook.

    Elm Leaf Beetle larvae in Denver

  3. European Elm Scale

    Elm Scale is one of Colorado’s most widespread and destructive insects. Heavy infestations cause premature yellowing and shedding of leaves and branch dieback. The scale can kill young elm saplings. The insect produces honeydew with peak production in early June to early July, covering parked cars, patio furniture, and sidewalks underneath infested trees. Click here for more information about this tree pest.

  4. Emerald Ash Borer (EAB)

    Homeowners might think we are a crying wolf, but the EAB may be in Denver already. The iridescent flathead borer arrived in Colorado in 2013 and has spread to Boulder, Gunbarrel, Longmont, Lafayette, Lyons, Superior, Broomfield, Westminster, Arvada, and Fort Collins. The insect attacks Green, White, Black, and Blue Ash. The tree borer is hard to detect because most of the harm is unseen underneath the bark, so prevention is the best way to save mature Ash trees.  With 1.45 million Ash in the Metro Denver area, the death of that many trees would be catastrophic to the area’s urban forest and reduce home property values. City foresters in Denver and surrounding suburbs expect homeowners to manage the Ash on their property. It stays once found in a city, but annual treatment keeps trees safe from the borer. For more information, please check out the Ross Tree EAB Handbook.


Homeowners needing help getting their trees ready for the spring should call Ross Tree at 303-871-9121 or click here to fill out a tree service form.