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Case Studies


This client in Dana Point had multiple issues affecting an olive tree. The tree was infested with a pathogen known as bacterial leaf scorch (xyella fastidiosa) which is easily spread among  trees by the glassy-winged sharpshooter, an insect. The tree encountered heavy die-back from inhibited translocation of moisture. 

Gruett Tree Company injected a systemic insecticide to take care of the vector for the bacterial pathogen and an antibiotic for the bacteria. A growth regulator was applied to slow down the metabolism of the tree to allow time for the antibiotic to work. The olive tree is now flourishing!



This oak tree was one of two that were growing in the middle of a lawn in soil with high clay content. They were suffering the effects of receiving too much water, which included root rot caused by phytophthora algae, which is one of the most difficult soil-borne pathogens to control. Our professionals not only had to treat the tree, but the surrounding soil had to be re-structured. The after picture on the right is a new tree planted by Gruett because the first two could not be saved and died. That tree is now thriving in the yard. Another new tree also began to fail, so we took it out of that environment and back to our nursery, where it is now thriving as well.


CASE STUDY #3: Saving a Coral Tree

This coral tree in North Tustin was hit by the Kuroshio shot hole borer (KSHB), was planted in compacted soil, and had uptake issues, and little to no root structure and very poorly aerated soil. We treated the beetle with systemic insecticides and fungistatics. We then restructured and re-mineralized all of the soil around it and used a systemic growth regulator to help the tree better absorb water by itself. The photos shown here were taken 1 year apart.


CASE STUDY #4: Renewal vs. Removal

Below is a sweetshade tree in Orange that was declining to the point our client wanted it removed. When we inspected the tree, we found major dieback, scale infestation, and water-logged soil.  We treated the tree systemically with insecticide, restructured and aerated the soil, applied fungicides and removed the scale by hand. The patient is still undergoing treatment, but is making a speedy recovery. The photos were taken in August 2019, and March 2020.


Gruettville Gazette - Monthly Newsletter

For years, Gruett has always done its best to bring valuable tree healthcare content, tips, tricks, and even specials and coupons to our community through the Gruettville Gazette. We invite you to take a look at some of our past issues and take a walk down memory lane!

MARCH 2020
JULY 2020


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Did you know that there are only a handful of tree companies that are actually qualified contractors? That’s what makes Gruett Tree Company a safe choice when looking for a bid in Orange County and throughout Southern California. Gruett Tree Company is fully licensed, bonded and insured. Click here to view our license.

To protect you and your property, a professional contractor should be licensed, bonded and insured. The state board of contractors requires a professional to have a valid contractor’s license. Ask for proof of insurance commonly referred to as a general liability and workers compensation coverage. A license should be a class C61-D49. This is not to be confused with a landscaping license, which is a class C27. Should an incident occur, your homeowners insurance could question the validity of your claim. For landscapers and gardeners, the insurance will not cover such loss.

A business license does not qualify as a state contractor’s license. Although a professional tree care company should have both, they are separate licenses. Gruett Tree Company’s contractors license is #707165 C61/D49.


• Over 35 years of experience.
• Documented quality work and client base. Referrals available upon request.
• A California Corporation
• State of California Contractor License #707165.
• Classification C61 – Speciality in D49 Tree Service C61-D49
(The only tree service license recognized by the state of California)
•Classification C27 – Landscaping
• $2,000,000 General Liability
• $1,000,000 Worker’s Comp
• $1,000,000 Commercial Auto Insurance Policy

Gruett Tree Company Team Members all posses at least one of the following:

• Ariel Rescue Certified
• CPR Certified
• Crew Leader Specialist
• Ground Operations Specialist
• Tree Climber Specialist
• Ariel Lift Specialist
• Certified Tree Worker
• Certified Arborist

The Above certifications are all backed by comprehensive training both on and off the field. ALL training, and certification is backed and endorsed by the leaders in our Industries standards. By providing our team members with the tools and support necessary we are able to ensure that Gruett Tree Company’s quality of service and safety measures continue to be that of a model company.

Gruett Tree Company is a proud affiliate of the following programs:


We maintain trained, professional arborists on staff and are dedicated to ethics and quality in business practices. We are a recognized member of the Tree Care Industry Association (TCIA) because of our stringent safety and performance standards for quality and safety. TCIA provides accreditation and certification services for tree care companies and professional arborists. TCIA also provide safety and educational programs, guidelines for tree service operations, ANSI A300 tree pruning standards, and much more.


The International Society of Arboriculture strives to raise the standards of professional tree care, and offers thier coveted ISA certificate only to those tree care companies that meet and hold the highest standards in the business. Gruett Tree Company is proud to staff multiple ISA certified Arborists. When you have a Gruett Arborist look at your project you don’t just have one perspective, you have multiple perspectives. Gruett consults with Board Certified Master Arborists to ensure that your final report is comprehensive and objective.


The California Landscape Contractors Association offers a wide range of programs and services to members of the landscape industry, and has accredited Gruett Tree Company with certification for passing their hands-on field tests and landscape skills.