Plant Health Care 


What is Plant Health Care?

Plant Health Care (PHC) is a holistic approach to caring for your trees, shrubs and herbaceous plants, with the goal of improving and maintaining the health and aesthetics of your landscape. A true PHC program draws from different strategies including cultural, biological and pest/disease control treatments. Cultural methods are the foundation to a healthy and sustainable landscape. This involves thoughtful selection and placement of new plant materials, proper planting techniques, adequate watering, mulching, soil improvement and pruning to promote health and mitigate tree failure. Biological control includes the use of natural parasites, pathogens and predators of pests. Many of these beneficial organisms exist naturally in the landscape and can be promoted by increasing plant material diversity. Certain pests and diseases will require treatment, for which we utilize a broad array of natural, organic, and synthetic products. Many of these products are considered to be “biorational”, a word to describe products that have low environmental impact. For more information on biorational, we recommend these university extension sites. UVM and UMass


Why is plant health care important?

Trees are inherently at a disadvantage when growing in a planted landscape setting due to turf competition, lack of soil microorganisms, compaction, poor drainage and low levels of organic matter. In addition, with the continued effects of climate change creating unpredictable weather events such as drought, wet spells and an overall warming trend, we are seeing higher levels of pest and disease pressure on plants that may already be under stress due to these weather extremes. The trees, shrubs and herbaceous plants that compose our landscapes contribute immensely to the health, function and value of the property, and need to be managed properly to increase long-term benefits. Chippers certified arborists will evaluate your landscape and build a custom PHC program that is suited to your specific needs.


Assessment & Monitoring

The first step to addressing plant health problems is to properly identify the host plant and the pest or disease (biotic factors) affecting the plant. We often take plant tissue samples for laboratory analysis to aid in identification or verify our field diagnosis. We also investigate environmental factors such as soil compaction, low fertility or improper planting depth (abiotic factors). These conditions are often the “root” of the problem and must be corrected first  or in combination with a pest or disease problem. Our licensed, trained and dedicated technicians build a strong working relationship with our clients and over time gain a deep understanding of each client’s landscape. This creates a stronger PHC program year-after-year as we learn what specific issues are common in a landscape, allowing us to be proactive and make modifications to annual programs.


Programs & Product Choices

Awareness and concern continues regarding the long-term effects of synthetic pesticides, pollinator decline, and the overall health of our ecosystems. We are excited to offer biorational and hybrid programs that focus not only on the health of the individual trees and shrubs, but also on the health of the soil and surrounding ecosystem to foster an environment where your landscape plants will thrive.


Biorational Program

Our new biorational program uses organic, natural and biorational products. Biorational products have the ability to control many common pests and diseases with minimal disruption to the environment and its inhabitants. Some of these products are synthetic, but are recognized by the EPA to have very low environmental risks and break down rapidly into harmless byproducts. This program is well suited for sensitive areas or waterfronts, and people who wish to use only the lowest impact products available. Many of these products are certified by the Organic Materials Review Institute (OMRI) and are approved for use on organic certified properties and farms. For more information on the term biorational, we recommend these university extension sites. UVM and UMass


Hybrid Program

The new hybrid program allows our technicians to use a broader array of products including organic, natural, biorational and non-biorational synthetic. It is important to understand that some pests and diseases can only be effectively controlled with non-biorational synthetic products. However, by using targeted application techniques we can achieve control of these difficult pests and diseases with minimal impact to the environment. This program is ideal for landscapes that experience more severe pest or disease outbreaks or landscapes that may require the use of certain products not considered to be biorational. However, we always strive to use the lowest impact treatments whenever possible.


Biostimulant Applications

Our proactive programs mean that if insects and disease are at or below an acceptable threshold, then a visit may consist of applying a biostimulant to feed beneficial soil organisms, boost plant growth, and increase plant health naturally. These products may contain different types of beneficial microorganisms, trace nutrients, and humic acid. Vigorous trees and shrubs that are growing in biologically diverse and healthy soil are much more resistant to pest and disease outbreaks and environmental stressors.


Specialized Injections

We utilize the latest in advanced technologies to inject directly into the cambial layers of a tree with minimal damage for treatments of varying insects and diseases such as Dutch elm disease, boring insects and bacterial blights.  We can also treat for growth and seed/flower reduction. 

Miscellaneous Treatments

  • Deer Repellents
  • Soil Amendments
  • Specialized Post-Construction Fertilizer Solutions
  • Mycorrhizae (friendly fungus) Root Zone Treatments
  • Herbicide Applications
  • Soil Injections for Birch Borer and Leaf Miner  


Tree & Shrub Fertilization

Our special custom blend is a high-percentage, slow-release, zero-phosphate fertilizer with added bio-stimulants. Methodically applied in either the spring or fall, it nourishes and sustains your trees or shrubs. We use a hydraulic system which is difficult to replicate without the use of high pressure pumps and soil injection devices for optimum delivery of the product in large volumes.


Landscape Health Assessment

Our consulting professional examines a single plant or entire groups to determine the best approach for maintaining or improving the health of your landscape.


View past issues of our GreenWords newsletter, and print pdfs of our Notes from the Arborist information sheets.

Invasive (Exotic) Pest Watch

There are some very destructive insects closing in on the Northern New England area. These insect pests are called exotic because they are not native to our country and they have no natural enemies. These three are currently considered to be the most threatening:

1) Emerald Ash Borer (EAB)

The Emerald Ash Borer (EAB) is an invasive beetle that has killed hundreds of millions of ash trees in North America since its discovery Michigan in 2005. As a non-native insect, EAB lacks predators to keep it in check. The larvae of the beetle attack ash trees and the infested trees die within three to five years. 

EAB is in NH

EAB was first detected in NH (in Concord) in 2013 and has spread to Hillsborough, Merrimack, Belknap and Rockingham counties. A quarantine of all hardwood firewood, ash wood-products and all ash nursery stock is in effect for these four counties. For more specific locations for both NH’s infested and alert areas, click on this PDF. Ash trees make up about six percent of New Hampshire’s northern hardwood forests, and it’s a commonly used landscape tree.

Just a Matter of Time for VT

So far, EAB has not been detected in Vermont, but has been detected in all states and Canadian provinces surrounding Vermont; clearly it is coming. “Ash was widely used to replace the stately elms that graced our communities and were decimated by Dutch elm disease in the middle of the 20th century and have historically been a favorite choice for street trees in Vermont due to fast growth and salt tolerance.” (not sure how to identify the source of this last sentence, it was from Steven Sinclair, director of forest for the state Department of Forests, Parks and Recreation, Rutland Herald, May 4, 2014.)


Emerging females mate and lay eggs individually in bark crevices on the trunk and major branches.  The eggs hatch in about a week with the small larvae boring through the bark into the cambium area where they feed on the phloem and create long, serpentine galleries.  Larvae continue development through the late summer and into the fall when they begin the pupae stage and emerge as adults in the spring, leaving 3-4mm wide D-shaped holes. EAB can be present in a tree for two years without signs of decline. Eradication is difficult and painful, requiring the removal of thousands of trees in the quarantined areas.


Individual high-value trees can be saved by treating them with insecticides, but it is best to treat preventatively, before the tree is attacked. Products are applied to the soil or bark, early or throughout the growing season. Curative, cambial treatments may be effective if caught early enough.  In terms of controlling the spread of EAB, the NH Division of Forests and Lands has recently discovered some positive results using parasitic wasps as biocontrol. This process requires wasp larvae to be injected into the ash trees where they can actually develop inside EAB larvae. The wasp larvae will then eat their way out of the EAB larvae to become adult wasps that will continue to feed on the EAB larvae as well as their eggs. This could prove to be very successful because the parasitic wasps will reproduce aggressively and only face minimal food competition from woodpeckers. While early findings offer hope for a solution it will require a good deal of additional testing and could prove to be very expensive. 


2) Asian Longhorned Beetle (ALB)

Native to China and other parts of eastern Asia, this insect hitched a ride to the US in crating material shipped to NYC in the 1980s.  It has affected areas in New York, New Jersey and Chicago, IL.  More recently, and of greatest concern to New England, was the discovery of ALB in Worcester, MA, during the summer of 2008.  Removal of 6,000 infested trees began in January of 2009.  Host species include all of the maples, horse chestnut, poplar, willow, birch and elm.  

The ALB will travel up to 400 yards in search of host trees but is more likely to make it to our area in firewood.  Its lifecycle begins when a mated adult ALB chews individual depressions into the host tree's bark where it lays its eggs.  Within a few weeks the larvae emerge and tunnel into the tree, eventually endeing up in the heartwood where they pupate, become adults and exit the tree leaving perfectly round one inch holes, usually in the spring and summer. Eradication is difficult and painful, requiring the removal of thousands of trees in a quarantined area.

3) Hemlock Woolly Adelgid (HWA)

This insect pest appears to have originated in southern Japan and was introduced to the Pacific Northwest in 1924.  Its introduction to the northeast was probably in 1951, first reported near Richmond, VA.  To date it has affected more than 16 states from Maine to Georgia.  HWA is dispersed by wind, birds and other forest-dwelling mammals as well as by the transport of infested nursery stock.

HWA threatens the health and sustainability of the Canadian and Carolina hemlock species.  Hemlock decline and mortality typically occur within four to 10 years of infestation in our northern range.  These parthenogenetic insects (all females reproducing asexuallly) develop through six stages, completing two generations per year on hemlocks.

It is during the heat of the summer the nymph enters a period of dormancy, feeding as temperatures cool in the fall and throughout the winter.  HWA feed on stored starches critical to the trees' growth and long-term survival.  The 'wool' (ovisacs) can be seen from late fall to early summer on the underside of the outermost branch tips of hemlock trees.  Control is possible in the urban landscape utilizing various chemcial pesticides along with horticultural oil and insecticidal soap.  Unfortunately, our forests face the greatest risks.

To report an invasive pest in Vermont or New Hampshire, contact:

Mark Michaelis
State Plant Health Director
617 Comstock Road, Suite 2
Berlin, NH 05602-8927
Phone: 802.828.4490
Fax: 802.828.4591


 Please email for more information about any of the services listed on this page.

Click here for a pdf listing of all of our Green Care Services.