Jerry White

Arbor-wellness: Fire Blight

This time of year, it is often easy to spot an ornamental pear in the landscape because it will often have burned tips with brown leaves at the tip of branches. This is a classic symptom of a bacterial disease called fireblight. This difficult to control disease starts in the spring by small infections at the tip of a branch and moves further down the branch during the spring, killing as it goes. The result is the blackened tips that usually have a bend or crook in them, similar to a “shepherd crook”.  Ornamental Pears are the most common tree in the landscape in our region that get fireblight, but apples, firethorn, crabapples and several other species are also susceptible.  Click here to find out about fireblight control and how Arborwell can help prevent this on your trees.

My trees seem to be dying at the tips, what is this?

If the tips are crooked, the color is dark brown to black and the tree is in the apple family, it is probably a bacterial disease called fireblight.

How do I suppress it?

Fire blight is a bacterial disease so it behaves somewhat differently that most fungal diseases and control of it can be a little more complicated. Fall or winter preventative treatments are the most cost-effective way to suppress fireblight on susceptible trees. If your trees are already infected, we treat with an antibiotic injection as well as the preventative treatment. These two treatments together seem to be very effective.

What kinds of trees get fireblight?

Trees and shrubs in the apple family are susceptible to fireblight. This includes Apples, pears, crabapple, hawthorn, loquat, mountain ash and toyon and shrubs like firethorn and rose. Because it will spread by wind and rain from one type of plant to another, treating all the susceptible plants on your site is usually a wise idea.

How do I get rid of the dead tips, there seems to be a lot of them?

Proper pruning is really critical when you have fireblight. Pruning needs to remove all of the infected stem, so knowing how far down to make the cut is very important. Disinfecting the tools used to prune with is also important because bacterial spores from an infected tree can transport fireblight to other trees very readily. Timing of when to prune is also important. When a tree is pruned during the time fireblight is active, new infections can more easily occur.  At Arborwell, we know how to make a good management plan for your ornamental pears and other susceptible trees that maintains their health and safety for years to come. Contact your Arborwell certified arborist for professional management of fireblight and all your tree needs.

Fire Blight, plant health care, trees

tree wellness

Arbor-wellness: Preventative Care

Fall & winter are the most valuable time to consider being proactive with many of next seasons spring and summer pests. Whether its sticky sap, borers and bark beetle, leaf diseases like anthracnose or even trunk or tissue cankers, when we make a treatment in the fall or winter, we are protecting your trees for an entire season. This makes the most sense, given the stresses our trees have had to overcome the past several years. It is said that for every year of significant stress, at least one full year of good growing conditions are needed for a tree to return to proper health. Stressed trees are more prone to insects and diseases because their defense systems are weakened and they have a harder time protecting themselves. So along with proper pruning, watering and mulching, protecting against insects and diseases will help them become healthy again.

My trees seem to be struggling still, why is that? 

Well most likely they are still recovering from the stresses of the drought we have had. When trees are stressed, whether it is drought, lack of irrigation, flooding, or whatever stress has occurred, they reduce the output of new leaves and new roots. They don’t produce as much energy storage and the stop producing the compounds (auxins and enzymes) that they use to ward off attacks. Thus, they become more vulnerable to damage from insects and diseases.

Will they die?

Its hard to determine that without a good evaluation from a certified arborist. That being said, providing extra “help” for them right now is very beneficial to their recovery. Just like a marathon runner that starts out in good shape, if that runner is forced to run back to back to back marathons without the time to recover well, they become more prone to injuries and illnesses. Allowing for proper recovery allows them to run another marathon (another stress) down the road. So, trees need this recovery period too, reduced stress from lack of water, excess heat, over watering and attacks from diseases and insects, so they can build their defense systems again, like we need to recover our immune systems.

How do I help them recover?

First reduce additional stresses – proper watering, mulching, pruning are key components to helping your trees recover. Second, by proactively protecting a tree from insects and diseases, they have a further chance to build those defense systems. If an insect – like caterpillars for instance, defoliates a tree next spring, that tree has to put new leaves out a second time. The same goes for diseases like anthracnose or fireblight. The energy the tree expends by putting out a second set of leaves prevents it from building up its defense system again, thus prolonging the recover. If this weakened tree is subject to another multi-year drought cycle, the chance of it surviving is even lower.

When is the best time to treat my trees?

Fall and early winter are the best times by far. This allows ample time for the systemic treatment to completely circulate throughout the tree. It allows the treatment to be ready as soon as spring growing season starts again.  Late winter and early spring are the second-best time. It is still early enough to have the treatment be effective under most circumstances.

 What kinds of problems can you control proactively? 

Many of the most common insects and diseases can be suppresses this way.  Insects that produce sap, most boring insects, most scale and thrips, adelgids, caterpillars and twig boring insects for example. As far as diseases go, preventing is so valuable, because by the time you see a disease on a tree, the damage has essentially been done. This is true for fireblight, anthracnose, powdery mildew, root rots like verticillium and phythophera and stem and twig cankers and needle blights on evergreens.  Lastly a nutritional supplement can be applied at the same time. Many times, a tree is stressed in part because of the lack of available nutrients in the soil. We can provide a balanced, organic nutritional supplement that will give your trees a proper feeding. Or better yet, we can sample your soil and replace exactly what your trees need.

Fill out the form below to get in contact with one of Arborwell’s ISA certified arborists and create a prevention plan for next year.


Who we serve

A Brief History Of Seattle

Seattle and Its Trees: A Brief History

In many ways, trees define the history of Seattle.

Europeans who settled in the Northwest saw the region’s forests as an economic opportunity. Seattle and the state of Washington became famous for its majestic trees, which included stands of cedar, hemlock, spruce, and Douglas fir.

With eastern U.S. forests depleted by the 1850s, the regional timber industry around Seattle expanded. The concept of sustainability was virtually unknown, and clearcutting provided wood for construction in the city and throughout the country.

The logging industry, along with the California Gold Rush, spurred Seattle’s growth in the latter part of the 19th century. Mills dotted the landscape around Seattle. Until the disastrous fire of 1889, most homes and buildings in the city were wood. Wooden ships built in Seattle transported timber to San Francisco.

Eventually, lumber companies, unions, the government, and the public realized that unfettered logging could not continue. Residents elected representatives who helped to preserve large areas of trees with laws, regulations, and sustainability practices.

In the late 20th century, Seattle’s trees also came to be regarded as a cherished resource. Mature trees characterize many neighborhoods and parks and organizations such as the local agency Trees for Seattle seek to preserve trees and educate the public about their value.

Today, Seattle has a diverse population of trees. Before Europeans moved in, several dozen types of trees inhabited the Seattle area. As the city grew, many more species were introduced, thriving in the region’s temperate, moist climate. Due to the effort of public and private enterprises that promote tree plantings, observers say there are nearly 1,500 tree species in and around Seattle today.

Seattle’s Parks and a Legacy of Trees

Seattle’s trees play a crucial role in the construction of the city’s parks. John C. Olmsted, the stepson of the designer of New York’s Central Park, was commissioned in 1903 to create a master park plan for Seattle.

In addition to adding many trees to the city’s canopy by helping establish nearly 40 parks, Olmsted also worked to reinvigorate the appearance of existing parks. One stellar example of Olmsted’s legacy in Seattle is Woodland Park, north of the city’s Fremont neighborhood. Magnolia, beech, cedar, sycamore, and locust trees are among the species in Woodland Park.

American Forests, a conservation group, credits Seattle with having one of the nation’s best urban forests. Seattle’s municipal government conducts “tree walks” in many neighborhoods to heighten awareness and appreciation of the city’s excellent collection of trees.

Arborwell Works to Preserve and Enhance Seattle’s Trees

Arborwell supports Seattle’s status as a city that values its trees. Through a variety of services, we work to conserve trees and promote new plantings in Seattle and surrounding communities. 

Arborwell offers tree management programs, consulting, and health services to commercial clients who care about helping Seattle live up to its “Emerald City” nickname.

A report from one of our certified Seattle arborists is a valuable tool for companies that want to protect their property’s value by utilizing its data on tree conditions, sizes, location, and species.

As our history of Seattle illustrates, trees are a reflection of how much society cares about the environment. Let the professionals at Arborwell help you gain a deeper understanding of the trees on your property. For a consultation, call 888-969-8733 today.


seattle arborist, seattle trees

Arbor-wellness: Root rot and Cankers

How do I know if my tree has root rot problems or cankers?

Many symptoms of root rot mirror the signs of a pest infestation, which makes properly diagnosing it more difficult. The symptoms of root rot are sometimes easier to spot above ground. These can include:

  • Gradual or quick decline without an obvious reason.
  • Stunting or poor growth.
  • Small, pale leaves.
  • Wilted, yellowed, or browned leaves.
  • Branch dieback.
  • Thinning of the canopy.
  • On some species, the fungus grows up from the roots in the inner bark and causes cankers, or sunken dead areas.

The most accurate way to diagnose a root disease is to dig below ground to see if decay is taking place. If needed, samples can be taken to a lab and tested to determine exactly what type of rot is occurring.

What is the best way to take care of root rots and cankers?

Tree root diseases are best controlled by prevention. If you have existing trees, make sure they are being watering correctly, that soil or mulch are not allowed to build up around the base of the tree and that the soil is allowed to dry out between watering. Ideally soil should be well structured and should drain properly. Where conditions warrant, making systemic soil treatments can be very helpful. Fall timing of these treatments allows the tree to take the material in and distribute it throughout the plant for best protection.

Pruning out and infected root can help if discovered early and access is not a problem. Always be sure to disinfect any tools you work with before using them again. When roots are pruned, one newer biological treatment is to inoculate the roots with a special pathogenic fungi the feeding on the rot fungi. This is a natural defense system that has proven successful in orchards and tree plantations where some rots can become a severe problem over time. Once the root is inoculated and the “good guys” are established, ongoing treatments for root rot can be eliminated.

What about cankers or bleeding on the trunk?

There are many fungi that cause this and even some bacteria may be involved. Being able to accurately diagnose what type of problem the tree has is critical to developing an appropriated treatment plan. If you are concerned about trees on your site having root rots or cankers, contact your Arborwell arborist for a professional assessment and recommendation.

To get in touch with one of our certified arborists, fill out the form below:

sudden oak death

Arbor-wellness: Sudden Oak Death

What is Sudden Oak Death?

Sudden Oak Death is a disease that is lethal to several species of oak trees and damaging to well over 100 landscape plant and trees. It is primarily a woodland disease, in that the problem is more pronounced in the woodlands and savanna’s at the outskirts of our coastal towns. However, as the infections become more widespread, we see the effects of the disease more and more in urban areas.

How can I tell if my trees have SOD?

The disease starts by infecting leaves and twigs in the upper branches, but once it attacks a tree, it moves into the woody part of branches and the main trunk. This later infection is seen usually as open, bleeding wounds and cankers on the main trunks of the trees. It spreads during cool, moist weather and can be found in infected plant material, soil and even in the water that flows through infect areas. This makes control very difficult.

What can I do?

There are some very important steps to take in general. First, cleaning up debris on the landscape floor helps eliminate spores that spread the disease. Second, if you suspect you might have tree with this disease, ask your Arborwell arborist to confirm the diagnosis. We can confirm with the help of a professional lab if you have this disease on your site. Lastly, consider proactive treatments if the disease in in your surrounding area. Government agencies are mapping confirmed infections and recommend proactive treatments if your site is within ¼ to ½ mile of a confirmed infection.
There is a lot to consider when managing your trees for a long-term investment in health, safety and beauty. At Arborwell, we work hard to study and understand problems like Sudden Oak Death so we can offer the best solutions for YOUR site. Contact your representative today if you are concerned about your oaks, we will help you preserve them for you today AND for your children tomorrow.

To get in touch with one of our certified arborists, fill out the form below:

Arbor-wellness: Bark Beetles

What are bark beetles?

Bark beetles are common pests of pines, spruce, cypress, oaks and even elm trees. There are over 200 types found in California, of which about 20 are serious problems for us.

Why are there so many trees dying from bark beetles?

Our trees are still recovering from the 6 year drought a few years back. It will take several more years of good winter moisture before our trees have fully recovered. If there are additional stresses like compacted soil, excess salinity from reclaimed water or poor soil nutrition, it will take even longer. Because our trees are still weakened, they are not producing the auxins and other chemicals that help them ward off pests. Bark beetles and other pests have an easier time attacking and often killing trees that if healthy would problem not succumb.

Photo by Arborjet

How do bark beetles harm the trees?

Bark beetles in particular, lay their eggs inside the bark of trees. When the larvae hatch, they begin to feed on the living tissue just inside the bark layer. This slows or stops the transportation of water and nutrients up and down the tree. As they mature, they pupate into adults, exit the tree and look for more trees to attack. When enough bark beetle larvae are feeding on a particular tree, the tree can’t recover and dies. Sometimes the beetle will introduce a disease into the tree which either helps kill the tree, or increases the rate of wood decay, making it dangerous faster.

So what should I do?

The most important thing to do is improve or maintain the health of your trees. Proper summer watering, mulch, improving soil health and nutrition all help this process.
Secondly, be proactive about protection. Preseason applications can protect your trees for an entire season and are very cost effective compared to treating a tree after it has been infected.
At Arborwell, we can design a program to help your trees become and stay healthier, plus we can recommend the proper tool to protect your trees from bark beetles and from the disease they sometimes bring with them. Contact your representative today if you are concerned about your oaks, we will help you preserve them for you today AND for your children tomorrow.

To get in touch with one of our certified arborists, fill out the form below:

Arbor-wellness: Soil Nutrition

What’s wrong with my soil?

Poor quality soil has a major impact on the health of your trees. When soil is healthy, has the proper mineral balance and thriving microorganisms, trees naturally grow better, withstand stresses better and tend to fail less frequently. Poor soil conditions are often the underlying cause of tree decline and failures. It could be from compaction, poor soil water holding ability, excesses of salt or other minerals, or deficiencies of key micro-nutrients.

How can you tell if there’s something wrong with your soil?

Unhealthy plants are the most obvious indicator; however, there are ways to assess and determine more precisely what is wrong and – more importantly – how to fix those problems.

Just what is soil anyway?

It much more than just dirt that tracks into our houses, gets muddy when wet and blows around when dry and windy. The simple explanation is that soil consists of air, minerals and water. The balance of how much of those elements are in your soil go a long way to determining the actual health of the soil. However, soil is much more than just this.

Soil is an incredibly complex ecosystem that we usually think very little about. It’s role in tree health has been studied for a long time, yet we are still learning so much about how soil organisms interact with one another, with plants and with the soil itself. Because soil is so complex and in reality, very dynamic – what we do to soil affects very much the quality of the soil and its ability to help plants thrive. Because the very nature of being in an urban environment, natural soil conditions no longer exist around our buildings, in our parking lots and even in our parks. So how do we fix it?

“Essentially, all life depends upon the soil”– Charles E. Kellogg

To figure out what is wrong with your soil, you first need to understand what healthy soil actually is.

  • First soil minerals should be properly balanced. The main components that make soil have an ideal balance. We determine this from a basic soil test.
  • Second, we identify micronutrient excesses and deficiencies. These are the components that are critical to proper tree growth, but usually needed in small amounts.
  • Third we need to ensure that soil biology thrives. This becomes trickier because while these microscopic creatures are native to all soils, they need very specific conditions to truly thrive. These conditions include: proper soil moisture and temperature, enough air, a balance of minerals in the proper ratios and in particular, enough carbon in the soil. This can come in different forms and often the type of carbon is very critical as well. The good news is we can determine just what the potential of soil life is when we to a soil health assessment. This more complete analysis identifies the potential for your soil to thrive and indicates the obstacles to preventing that.
  • Lastly, we should pay attention to toxins, water management and mulch.

When we do a soil health assessment, we are looking at all of these factors to determine the best course of action to improve the soil for your trees. That is why our recommendations often include more that just fertilizer components. We strive to identify the limiting factors to YOUR soil and help you take cost effective steps to help improve the quality of your soil. This leads to many benefits for your trees and your sites.

How does healthy soil help your local site?

Let’s end the discussion by identifying some of the benefits of improving the soil conditions on your site:

Healthy soil 

  • Is less prone to erosion
  • Holds water longer
  • Holds minerals so they don’t leach into the water table
  • Meets the nutritional needs of your plants
  • Healthier plants are more resistant to insects and diseases
  • Healthy soil helps to filter toxins from the soil
  • Healthy soil supports good soil biology and reduces soil diseases
  • Creates a more sustainable environment for your property

To get in touch with one of our certified arborists, fill out the form below:


Arbor-wellness: Stop the Sticky Sap

What can I do about sap dripping from my trees right now? 

Many property owners have trouble with sap dripping off of their trees onto their cars and walkways. This sticky substance can be difficult to remove, accumulate dirt, and attract flies and other annoying insects. This sticky substance isn’t sap but is honeydew, and despite the name it has no relation to the fruit. Honeydew is the excrement of plant-sucking insects such as aphids, scale and certain whiteflies. This dripping is a telltale sign of an insect infestation.


What trees are most susceptible?

Insect infestations that lead to honeydew are frequently found on ash, crepe myrtle, elm, hackberry, oak and sometimes maple, willow, and fruit trees.


Does the honeydew hurt my trees? 

Honeydew by itself is annoying and a hassle when it drips on objects or the ground but will typically not hurt your tree. The real concern with the tree is the amount of damage the insects do to the leaves. Insects typically feed on stressed trees first, so this can indicate overall poor tree health too.


Can you stop the dripping?

Yes, we have specific products that are quick, effective and safe to use. They usually stop the feeding within 24-48 hours. HOWEVER, if there is a lot of honeydew on the tree, the dripping may continue for a while. The best answer in this case is to carefully wash the tree with a water solution to remove as much of the sap as possible. Cleaning of the sidewalks or roads can be done with a soapy water solution. Once you call your Arborwell arborist, we can assess the needs and provide appropriate answers. Remember too that we can easily prevent this in the off season to prevent the problem for next year.

If you are concerned about any diseases or sap on your trees and want to schedule an inspection, fill out the form below.


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